Lara Croft of Tomb Raider has had four voice actresses over 12 years and 8 games, each one bringing a totally different spin on Lara's personality. She even changes in appearance, and has been played in live-action promo shots by at least five different women, not even counting Angelina Jolie. She pretty much must be a Time Lord.
This is done deliberately so that no actress will be able to dominate the character.
Sofia Vergara played what is essentially the Angelina Jolie version of the character in this TV spot for Visa credit cards.
Max in Sam & Max: Season 1 was replaced after the first episode, though the voices are so similar it's not really that important - some of the original actor's voice clips have even been retained.
Before the big cast change, Tails went through several voice actors that were actual children (3 in English and 2 in Japanese), while Knuckles was voiced by Michael McGaharn in Sonic Adventure, Ryan Drummond (who also voiced Sonic) in Sonic Shuffle, and Scott Drier from Adventure 2 to Heroes.
Ultimately, if you count the short voice clips in Sonic CD, you would find that Sega has gone through 5 voice actors for Sonic. That's a lot compared to others.
The entire English cast of Valkyrie Profile changed between the first game and the second due to a switch in dubbing groups (TAJ Productions did the first game; Bang Zoom! Entertainment did the second). The only exception was Valkyrie Lenneth's voice actress, Megan Hollingshead, who voiced her in both; this was actually because Hollingshead had transitioned from TAJ/4Kids Entertainment (New York) to Bang Zoom! (California) a few years after the first game was released. Also, Kikuko Inoue voiced Valkyrie Hrist in the first game, and Atsuko Tanaka in the second.
Dante of Devil May Cry has had three voice actors, four if you count the one in the Japanese version of the anime. Only between games 3 and 4 did his voice actor (who, incidentally, is also his Ink Suit Actor) remain the same.
The same could be said of every recurring character excluding Lady (who has kept Kari Wahlgren as her voice actress since 3). The aforementioned Dante example is muddled further if one considers Dante's Special Guest appearance in the PS2 version of Viewtiful Joe. Although it came out a year after Devil May Cry 2 (where he was voiced by Matthew Kaminsky), Dante is instead voiced by his Devil May Cry voice actor (Drew Coombs). Thus, the voice actor progression went from Drew Coombs, to Matthew Kaminsky, then back to Drew Coombs, and then finally to Reuben Langdon, who has stayed as Dante's voice since the third game.
Cartoon Network: Punch Time Explosion video game replaced almost every voice actor since the game makers wanted to have a small cast. Only Grey DeLisle, Tara Strong, Keith Ferguson, and Yuri Lowenthal got to keep their roles. Some of the recasts were quite interesting. Grey DeLisle got to take over Blossom from The Powerpuff Girls, and Mac from Foster's Home For Imaginary Friends. Tara Strong voice both Bubbles and Buttercup, and also took over Dexter. Quinton Flynn took over Billy from Billy and Mandy (DeLisle reprised her role of Mandy), Lowenthal took over as the voice of Numbah One from Codename: Kids Next Door, Ferguson took over as Samurai Jack, and Nolan North took over "Father" from KND. The entire game only used a pool of eight voice actors.
Much to the chagrin of most fans of the franchise, the voice of Carmelita Fox in Sly Cooper was replaced in each game. She was played by Roxana Ortega in Sly Cooper and the Thevius Raccoonus, then by Alesia Glidewell in Sly 2: Band of Thieves, and finally Ruth Livier in Sly 3: Honor Among Thieves. It didn't help that each voice actress gave Carmelita a different accent.
And she's about to get Darrined again: Reportedly the upcoming Sly 4 will have her voiced by Grey Delisle.
Sarah Kerrigan, the penultimate Big Bad from the first StarCraft, is now voiced by Tricia Helfer for the ongoing StarCraft II sequel trilogy. Notably a flashback cinematic in the Wings of Liberty campaign, which featured Kerrigan's lines from the first StarCraft Terran campaign by her original voice actress Glynnis Talken-Campbell, were entirely redubbed by Helfer. Fred Tatasciore has taken over the role for Zeratul, as the original voice actor Jack Ritschel had passed away sometime before the production of Starcraft II. Patrick Seitz is the voice actor for Artanis in StarCraft II. All in all, only the voice actors for Jim Raynor and Arcturus Mengsk got to keep their roles from the original instalment.
Jim Raynor had a different voice actor complete with a very pronounced Southern accent in the initial gameplay trailers released for StarCraft II. Interestingly, Blizzard eventually changed their minds and brought back the original voice actor, Robert Clatworthy. But in a bizarre twist, Talken-Campbell initally confirmed that she was supposed to play Kerrigan in StarCraft II all along, and a released trailer showcasing storyboard sketches for the flashback cinematic actually featured her voice (and the redubbed lines for Jim Raynor complete with the Southern twang). Sometime after Clatworthy announced his reinstatement as the voice of Jim Raynor, Talken-Campbell took to the internet and announced that Blizzard decided to replace her as the voice for Sarah Kerrigan. Subsequent fan backlash never swayed the developers to reconsider their decision.
Goodson even voiced him in a ten-second cameo appearance in Soul Nomad & the World Eaters where Laharl wasn't even seen. It doesn't help that she voices another kid character with the same voice she uses for Laharl.
In an unusual inversion, when Lunar The Silver Star, was being remade into Silver Star Story, the original five English actors who did the original returned (along with other local talent from the area the Working Designs studio was), while all four Japanese voice actors from the original were replaced with an entirely new cast. The most notable change was Alex originally having Kikuko Inoue, and then going to Akira Ishida.
This occurs again in the Silver Star Harmony remake for the PSP, which was localized XSEED Games instead as Working Designs had long gone out of business. The story as to why depends on who you talked to - Victor Ireland, the former head of Working Designs, claimed the entire voice cast was loyal to him, aside from Jenny Stigle who "broke rank". XSEED, on the other hand, stated that most of the old cast wasn't actually in the business anymore, hence they hadn't tried to find them. Accordingly, Stigle got involved because fans of the original games put her in touch with XSEED. So which story you believe depends on who you trust more, though it was no secret that Ireland had a very bitter falling out with XSEED during the localization process.
The sequel, Lunar Eternal Blue, maintained consistent casts for both languages, on the other hand. The only change was Hiro's English voice going from Mark Zempel (Eternal Blue) to Chad Letts (Eternal Blue Complete), but they sound similar to the point that they're almost indistinguishable.
In the Prince Of Persia: Sands of Time series, the Prince's voice actor went from Yuri Lowenthal in the first game, to Robin Atkin Downes in Warrior Within, then back to Lowenthal for The Two Thrones, but with a slightly different voice and accent. Other characters' voices/accents (Farah and the Vizier) also changed between the games, and Kaileena's voice was not just changed between games, but changed during the game in Warrior Within.
Interesting international tidbit: the voice actor for the Spanish voice track was changed between Sands and Warrior, and the one from Warrior remained for Two Thrones. But what's interesting is that the first voice actor sounds younger and more arrogant, while the second voice actor sounds grimmer and older... which fits perfectly with the timeline of the game, since Warrior happens after a noticeable Time Skip, while Two Thrones is immediately after Warrior.
In the 3D The Legend of Zelda titles, Ganondorf was voiced by Takashi Nagasako, but for unknown reasons was replaced by Hironori Miyata in The Legend Of Zelda Twilight Princess. This is notable because unlike Link, Zelda, and other recurring characters, Ganondorf is confirmed to always be the same person in each game. Then again, a lot of fans probably didn't notice due to the series' lack of extensive voice acting.
But they most likely noticed in the Super Smash Bros series, where Ganondorf was voiced by Nagasako in Melee, and Miyata in Brawl.
Every Star Fox game has a different American (or in Star Fox Adventures's case, British) voice cast; in Super Smash Bros. Brawl, however, Jim Walker voiced Fox as he did in Star Fox Assault, and in their cameos, Mike McAuliffe returned to voice Slippy, and Alesia Glidewell voiced Krystal (Glidewell also voices Samus in that game.)
The Japanese versions aren't free from this; unlike most examples, though, they extended the cast and made more diverse voices (Star Fox 64 had only six voice actors for its many roles). One example is that Shinobu Satouchi voiced both Fox and Leon in 64; in Assault and Brawl Satouchi keeps Leon, but Kenji Nojima voices Fox instead. The only seiyuus who stayed throughout were Hisao Egawa (Falco), Kyoko Tonguu (Slippy and Katt in 64), and Tomohisa Aso (Peppy).
When the Star Fox 64 remake for the Nintendo 3DS was released, the entire Japanese cast had been replaced, with Egawa, Tonguu, and Aso finally dropping out.
In between Condemned: Criminal Origins and Bloodshot, lab tech Rosa Angel dropped 30 lbs and 20 years.
This was pretty common. Ethan, the Vanhorns, and Ferrel also got new voice actors (notable in that two of these four have the same actor, Paul Eiding).
Many major WarCraft characters have gotten a new voice actor for their World of Warcraft incarnation(although a few have retained their original lines). The most notable example would be Illidan, the Big Bad of the first expansion and many others directly connected to him.
At least Illidan's new voice actor sounds quite like his old one. Arthas (the titular villain of Wratch of the Lich King and the focal character for much of Warcraft III and it's expansion) was abruptly replaced after the first teaser for the new expansion, with what sounds like Peter Cullen. His voice actor allegedly thought he was getting the screws put to him and walked away. This is especially notable as the Lich King had previously been represented by two separate voices, one for Ner'zhul and one for Arthas, but now speaks with one reverbed voice that sounds nothing like either of the previous ones.
There is actually a bit of story to back this change up. A few of the quests in Icecrown show the Lich King basically destroying the part of the good Arthas that is still within him, so the voice change to one, solid voice makes a little sense.
Partway through the Wrath of The Lich King expansion, Sylvanas was abruptly re-voiced by a new actress who gave her a more prominent accent. Many fans of the character were upset with this, claiming the accent doesn't fit the character.
The voice of Sparx in The Legend Of Spyro series changes in each game, from David Spade to Billy West to Wayne Brady. In Dawn of the Dragon, when voiced by Wayne Brady, he tells Spyro that "[his] voice keeps changing" when Spyro asks how he feels.
Also Spyro himself has had many different voice actors as well: Carlos Alazraqui in the first game, Tom Kenny in the second through fourth game, Jess Harnell in the fifth and sixth games, and Elijah Wood in the current games even though he sounds nothing like the others, he may be an entirely different Spyro than the previous incarnation like his partner Sparx who originally spoke only gibberish in the original games.
After Spyro left Insomniac, each new game got a cast change for pretty much every recurring character, and often along with it, changes in personality.
The Xenosaga games had three entries in the series, and mixed and matched their actors throughout; for example, Episode 2 replaced Lia Sargent as Shion with Olivia Hack; Bridget Hoffman as KOS-MOS with Colleen O'Shaughnessey; Sherry Lynn as MOMO with Christina Puccelli; and Derek Stephen Prince as chaos with Joshua Seth. Episode 3 replaced Shion and KOS-MOS with their original voice actors while keeping the rest of the main cast from episode 2.
For Scarface: The World is Yours, Al Pacino could not reprise his role as Tony Montana as his voice had been altered by years of smoking, so he hand-picked André Sogliuzzo to do the voice acting, although the likeness remains Mr Pacino's. The difference in the voice is very difficult to notice.
They fortunately fixed this for the racing spin-off game, new actress or not.
Jak's own voice actor was replaced in TLF (from Mike Erwin to Josh Keaton). Given that early-stage production footage exists in which he's still voiced by his original voice actor, the switch is quite baffling. It seems most fans much prefer the original voice, with some even saying they won't bother picking up Playstation All Stars Battle Royale if Jak is voiced by "the replacement".
This has occurred with at least 3 characters in the Monkey Island series. Most notably, the character of Elaine Marley. In Escape From Monkey Island, she not only has a completely different voice actress, but she has also inexplicably dropped her British accent from the previous game. Oddly enough, she has both her original voice actress and her accent back again in Tales Of Monkey Island.
From Tekken 3 up until Tekken 6, the role of Heihachi Mishima belonged to Daisuke Gori. Following Gori's suicide, the role was given to Unshou Ishizuka (which also corresponds to Heihachi becoming younger for the release of Tekken Tag Tournament 2).
Also in Kingdom Hearts II, David Warner was invited back to voice his TRON characters Sark and The MCP, and apparently was very enthusiastic about revisiting the roles, but was unable to do so because of previous commitments. The parts were instead voiced by veteran voice actor Corey Burton, with many fans not even realizing it wasn't Warner.
Like with Star Wars, Corey Burton also replaced Christopher Lee as DiZ for RE:Chain of Memories, though this imitations is not as good as others of his. Strangely, Christopher Lee came back as DiZ in 358/2 Days.
Also related to Kingdom Hearts, but not Tron, they had replaced Naminé's Brittany Snow and even Kairi's (of all characters) Hayden Panettiere, with Meaghan Jette Martin and Alyson Stoner respectively, in Re: Chain of Memories and 358/2 Days. Alyson Stoner also voices Xion (it's significant later in the game).
Hayden Panettiere plays Xion in Kingdom Hearts 3D, making her the Other Darrin to Alyson Stoner. Confused, yet?
Perhaps most notable of all was the replacement of Ansem's voice actor Billy Zane with the decidedly less hammyRichard Epcar.
Plus in general, the characters voiced by big stars had their original voice actors not return such as Genie, Mushu, and Phil in Kingdom Hearts (or really any Disney property aside from the original film). Some of them such as James Woods (Hades), Angela Langsbury (Mrs. Potts), and David Ogden Stiers (Cogsworth) did return, however.
This became interesting in II, where two actors (Tate Donovan and Glenn Shadix) reprised roles they didn't do in the first game (Hercules and the Mayor of Halloween Town respectively). In other words, they became the other Darrins to their own other Darrins.
Almost the entire cast of The Lion King had new voices in Kingdom Hearts II with the exception of Pumbaa and Banzai and Ed who did have their original voice actors return. Young Simba and Mufasa had their original V As return by way of reusing audio from the original film. Also the entire cast of Pirates of the Carribean were replaced as the original cast was shooting the sequels and couldn't return (although they did want to).
Though this is all justified as the original Chain of Memories had mostly Voice Grunting and small phrases recycled from the original game (hard to get a fully voiced Game Boy Advance game).
Though Kingdom Hearts II was in production about the time. Its likely the International voice actors for Kingdom Hearts II were hired too much later to be incorporated in Chain of Memories so the Japanese voice actors were used instead due to them likely already being available for Kingdom Hearts II.
Justified for the voice of Mickey in Kingdom Hearts. After the passing of Wayne Allwine in May of 2009, Bret Iwan took over starting with Kingdom Hearts: Birth By Sleep.
The 5 main characters of The World Ends With You appear in Kingdom Hearts Dream Drop Distance and 4 of them are voiced by their original voices. They are Neku (voiced by Jesse David Corti), Shiki (Heather Hogan), Joshua (Aaron Spann), and Beat (Crawford Wilson). That leaves Rhyme, who was originally voiced by Kate Higgins, but in Dream Drop Distance, she is now voiced by Ashley Rose Orr.
The English version of the spinoff series Dynasty Warriors: Gundam had to recast all the characters, since Bandai couldn't get ahold of the men and women at The Ocean Group to have them reprise their roles. Also, one of the actors had left a long time ago.
In the second game, the voice for Judau changed from Sean Broadhurst to Andrew Francis.
Most of the original Voices did return for DWG. The only notable replacements were Heero (who's VA refuses to reprise the role after bad convention experiences) Domon (whose VA is now a dentist and no longer does voice acting).
Between Halo 2 and 3, the voice for Miranda Keyes changed from Julie Benz in the 2nd game to Justis Bolding in the third game. Although, they do sound pretty similar.
Princess Peach of Super Mario Bros. has had a multitude of voices, whereas Charles Martinet voices most of the male characters. For Peach, there is:
Mami Yamase: The Great Mission To Rescue Princess Peach!OVA.
Princess Daisy from Super Mario Land has had Kate Fleming for her return in Mario Tennis, Jen Taylor for most of the spinoff games, and, starting with Mario Golf: Toadstool Tour, Deanna Mustard, her current actress.
Rosalina had been voiced by Mercedes Rose in Super Mario Galaxy and Mario Kart Wii, but she voiced by Kerri Kane as of Mario Kart 7.
Any Resident Evil character that has been in more than one game will likely have a different voice actor per game due to Capcom's habit of changing casting agencies. One exception is Claire Redfield, who has been consistently voiced by Alyson Court since her debut in Resident Evil 2. An exception was almost made with Resident Evil Code Veronica, when Capcom considered using a local talent agency from Japan, but the Canadian studio that provided the voice acting for RE2 and Resident Evil 3 Nemesis successfully lobbied for her return.
Some characters have switched back and forth. Richard Waugh voiced Wesker in Code: Veronica, but was replaced by Peter Jessop in the GameCube version of the first game, only to return in 0 and 4, then he was replaced by DC Douglas in 5 and The Umbrella Chronicles.
Another aversion. Sally Cahill voiced Ada Wong in both of her appearances.
She was replaced by Megan Hollingshead in The Umbrella Chronicles, but returned to voice Ada in The Darkside Chronicles, and was then replaced again by Courtenay Taylor for Operation Raccoon City. Most of the regular VAs from the time of 4 onward (including the aforementioned people) also reprised their roles in The Darkside Chronicles, although most of characters from the games before 4 were given new voice actors.
Chris Redfield has been better in this regard, having three different actors between the original game, Code Veronica, and the R Emake, but ever since RE5 he has been consistently voiced by Roger Craig Smith.
Mortanius from Blood Omen: Legacy of Kain was originally voiced by Tony Jay, who would voice the Elder God in the sequels. To prevent confusion, they had Alastair Duncan voice Mortanius in Defiance.
After a contract disagreement with THQ, Richard Horvitz and Grant Albrecht were replaced as Pox and Crypto for the spin-off game Destroy All Humans: Big Willy Unleashed. The fans did not take to well to the replacement actors, but the originals came back for later games in the series.
In the Metal Gear Solid remake for GameCube, all the English voice actors from the original game reprised their roles with one notable exception: the voice of the Cyborg Ninja was changed from Greg Eagles (who was credited as George Byrd in the original) to Rob Paulsen. Eagles still reprised his other role as the DARPA Chief for the remake.
When Solid Snake and Roy Campbell appeared in Ape Escape 3, the localization staff were too lazy to track down David Hayter and Paul Eiding to reprise their role, so they got Peter Lurie (incidentally the voice of Vulcan Raven) and Michael McColl respectively.
Similarly, in Metal Gear Solid 3: Snake Eater, Raiden in the Secret Theater's Metal Gear Raiden: Snake Eraser was voiced by Charlie Schlatter, the same voice actor who voiced his Expy, Raikov.
In Metal Gear Solid 3, EVA was voiced by Suzetta Minet (although, given the reveal that she was actually an alias for another actress, exactly who played her is a subject of debate). However, in Metal Gear Solid Portable Ops, her voice actress was replaced with Vanessa Marshall for some reason (although to be fair, she never actually got any actual voiced scenes and at best did grunts), and in Metal Gear Solid Peace Walker, EVA was voiced by Suzetta Minet again.
In Metal Gear Solid 4, Liquid Ocelot's voice actor in the Japanese version was Banjo Ginga (the voice of Liquid Snake), not because of the fact that he was possessed by Liquid (hint, he was faking all along), but because Revolver Ocelot's original Japanese voice (Koji Totani) died before Metal Gear Solid 4 began production.
Master Miller was originally voiced by Cam Clarke, but the role was recasted to Robin Atkin Downes for Metal Gear Solid Peace Walker. This could be forgiven, though, since it was a younger Miller and Miller died before the events of the first Solid, with Liquid Snake (whom Clarke also voiced) assuming his identity.
The Substance rerelease of Metal Gear Solid 2 Sons Of Liberty includes a VR mission where you fight Meryl. For this fight, however, rather than recording new lines, they reused voice clips from Olga Gurlukovich's fight early in the main game. Though, since the two characters share the same seiyuu in the Japanese version, it's only a case of this in the English release.
Same for Rosemary's voiceovers in MGS3, where her lines are all done by the same actor as The Boss - it works in the original because both characters are voiced by Kikuko Inoue.
Backyard Sports has had four voice casts: 1997-2001, 2002-2003, 2003-2005, and 2006-present. All except 2002-2003 were made up of mostly the same people, but playing different characters each time.
Tenchu: The series in general, in both English and Japanese; they constantly changed studios from game to game. To mention the English examples:
Rikimaru went from Paul Lucas in the first game, to Rino Romano in the second, to Daniel Dae Kim in the third and Liam O'Brien in the fourth.
Ayame went from Terry Osada in the first game, to Debi Mae West in the second, to Michelle Krusiec in the third and an unknown voice actress in the fourth.
As for other characters, Onikage went from Seiichi Hirai in the first game to Paul St Peter in the fourth; while Tatsumaru went from David Moore in the second to Quinton Flynn in the third.
In the Syphon Filter series, Mara Aramov had a different voice actress in the first four games. Lian Xing has been voiced by three actresses; Ava Fang in 1, Zoe Galvez in 2 and 3, and Kim Mai Guest (the voice actress of Mei Ling) in all subsequent games, complete with different looks and personalities. Gabe Logan also switched voice actors from John Chacon to James Arnold Taylor starting with The Omega Strain.
Magneto and Colossus lose their well-known voice actors (Tony Jay and Earl Boen) for the X-Men Legends sequels, in which they were replaced by Richard Green and James Ward respectively. Cyclops and Pyro (both voiced by Robin Atkin Downes) were also recast so Josh Keaton and John Kassir took his roles.
This trope carried through to the Marvel Ultimate Alliance games, though more noticeably in the second. Some actors stayed on from X-Men Legends, though by the second this became far less frequent and often actors staying on were cast in new roles. By Ultimate Alliance 2, the only actors reprising roles from previous games were Steven Blum as Wolverine, John Kassir as Deadpool, April Stewart as Ms. Marvel, Dawnn Lewis as Storm, and John DiMaggio as Juggernaut. Fred Tatasciore reprised his role as Hulk from elsewhere, replacing Peter Lurie from the previous game.
Al Pacino did not allow EA to use his likeness or voice for The Godfather game, so Michael Corleone's appearance and voice were replaced.
While Street Fighter does this frequently, the most notable cases are...
Street Fighter III. 3rd Strike replaced everybody save Akuma (Tomomichi Nishimura) and Ibuki (Yuri Amano).
In the Japanese version of Street Fighter IV, everybody is recast except for Ken (Yuji Kishi from Street Fighter III 3rd Strike onward), Blanka (Yuji Ueda as of Street Fighter Alpha 3), Makoto (voiced by Makoto Tsumura in both of her appearances), Yun (Kentaro Ito from 3rd Strike on), Yang (Masakazu Suzuki from 3rd Strike on) and M. Bison (Norio Wakamoto as of Capcom vs. SNK). Curiously, Yuji Ueda does not reprise his role as Vega, instead being replaced by Junichi Suwabe, and Toru Okawa is no longer Ryu, but his master Gouken.
In Koei's Samurai Warriors, Toyotomi Hideyoshi's American voice actor portrayed him with a screeching, annoying voice. In Samurai Warriors 2, with Hideyoshi's role in the story expanded, he was assigned a much better actor who was able to convey a great deal of depth and humor, making him much more tolerable. And then Warriors Orochi hit, they went back to his old voice actor.
Athena Asamiya is the uber-example of Darrining. She's had five seiyuus: Reiko Fukai (KOF '94) to Moe Nagasaki ('95) to Tamao Satou ('96) to Yukina Kurisu ('97) to Haruna Ikezawa ('98). They've seemed to have stuck with Ikezawa since though.
Robert Garcia is an interesting example. His first voice actor (Eiji Yano in Art Of Fighting) was replaced by Kazuhiro Inage for Art of Fighting 2, The King of Fighters '94 and '95. After that, Mantaro Koichi replaced him for Art of Fighting 3 and The King of Fighters '96, and provided Robert's voice for every game up to KOF 2003. Then in Neo Geo Battle Coliseum, Inage returned to voice Robert and has done so ever since.
Overall, however, SNK is a large aversion of this trope, with most voice cast changes only happening when the company has lost contact with a seiyuu, the seiyuu retires, or (unfortunately) the seiyuu passes away. This means that a vast majority of their characters have been voiced by the same person on at least a semi-regular basis for a good period of time, some even approaching 10 or 20 years of voicework.
Mega Man Legends: Mega Man Volnutt's voice changed between the first and second games; from the then-child actor Corey Seiver in the first to Susan Roman in the second (in other words, they went from averting Crossdressing Voices to playing it straight). Seeing as how both games were recorded in the same studio (and the rest of the cast remained unchanged), it was probably due to Corey reaching puberty between the two.
Less notably, Glyde also suffered a voice change between The Misadventures of Tron Bonne and Mega Man Legends 2, going from Michael Daingerfield Hall to Toby Proctor. Tron Bonne herself remained consistent throughout the PSX games (being voiced by Caroly Larson), but was voiced by Tara Platt in Marvel VS Capcom 3.
Mega Man (classic): Ignoring the various cartoons (from both sides of the pacific) based on the franchise, only two games in the series featured voice overs: Mega Man 8 and Mega Man Powered Up, both recorded in two different studios. Thus, Mega Man has been voiced by Ruth Shiraishi in 8 and Cole Howard in Powered Up. Roll was voiced (respectively) by Michelle Gazepis and Angie Beers, Proto Man by Jack Evans then Jonathan Love, Dr. Light by Darryl Stogre and Randall Wiebe, and Dr. Wily by Douglas Kendall and Dean Galloway.
Mega Man X: The series has circulated through three studios, so:
X was voiced by Ruth Shiraishi in Mega Man X4, Peter von Gonn in Mega Man X7 and Mark Gatha from Mega Man X8 to Mega Man: Maverick Hunter X. Additionaly, Ian James Corlett voiced him in the Ruby-Spears cartoon.
Zero was voiced by Wayne Doster in Mega Man X4, Jack Merluzzi in Mega Man X7 and Lucas Gilbertson from Mega Man X8 to Mega Man: Maverick Hunter X. Additionaly, in Marvel Vs Capcom 3, he is voiced by Johnny Yong Bosch.
In Japan, Zero was first voiced by Ryotaro Okiayu in Mega Man X4, but when the first Mega Man Zero was released, he was voiced by Yuuto Kazama. This is a strange case, because Capcom hires either one of these actors depending on which form of Zero is being used (Okiayu for X series Zero and Kazama for Zero as he appears in his own series) and they have always reprised their roles respectively.
Sigma was voiced by Charlie Fontana in Mega Man X4, Walter Roberts in Mega Man X7 and Gerald Matthews in Mega Man: Maverick Hunter X. He was also voiced by Dave Pettitt in Mega Man X8, but it's debatable whether it counts (long story).
Rather irritatingly done within the same game in Heavy Rain for the DLC The Taxidermist, where the character of Madison Paige (the only returning character) quite blatantly has a completely different voice. This was because The Taxidermist had been created as a gameplay demo a couple of years before release, when the final voice actors hadn't been cast. Quantic Dream just decided to save the trouble of recording Madison's lines again with the actress from the main game.
Fans of Quantic Dream's previous games will notice that Madison's voice actress for The Taxidermist is actually Carla Valenti from Indigo Prophecy.
Although James McCaffrey voiced the character in all three games, in Max Payne series writer Sam Lake modelled for Max in the first game, was replaced by the irreconcilably different-looking Timothy Gibbs in the sequel owing to the project's bigger budget, and then in the third game Max is modeled after his actor. Lampshaded in one of the second game's fourth-wall-breaking dream sequences, when one of Max's doubles looks at himself and says "I've been switched! I didn't use to look like this!"
Max was originally to have a different voice actor in the third game, due to the Time Skip. However, Rockstar bowed to fan outcry and cast McCaffrey again; it helps that, with the long period of development, McCaffrey had aged about the same rate Max had between the two games.
In the first Star Trek Elite Force game, each of the main characters was voiced by their original actor from Star Trek: Voyager except Seven, who was voiced by Joan Buddenhagen. Then when the expansion pack was released, Jeri Ryan stepped in to provide Seven's voice, even going so far as to re-record all of Seven's lines from the original game so there wouldn't be an obvious change when going from original to expansion material.
One of the changes made for Golden Eye Wii was to replace Pierce Brosnan's James Bond with Daniel Craig. To make the replacement less jarring, all of the other characters in the single player campaign have also had their appearances completely altered as well. They're all new designs (some based on the voice actors), but it does fail a little in terms of polish.
Marty McFly in the newer Back To The Future video game is not voiced by Michael J. Fox (for understandable reasons), but by a voice-acting newcomer named AJ Lo Cascio. So the story goes, when AJ first spoke his lines as Marty during a recording session, it was similar enough to Fox that it completely surprised Christopher Lloyd.
Later on however, Michael J. Fox voiced multiple characters in the fifth episode of the game ("OUTATIME") as cameo roles.
Biff Tannen and George McFly have been given new voices in the form of Kid Beyond and Michael X. Sommers (respectively, who also voice Kid Tannen and Arthur McFly), replacing Tom Wilson and Crispin Glover.
Video game versions of Mobile Suit Gundam in America tend to go through Other Darrin moments. Among those were any game that used Heero Yuy (as his voice actor hated the character due to how he was treated during recording of the series) and Domon Kasshu (according to the voice actor of Mega Man X character Zero, his voice actor had disappeared off the face of the Earth; Wikipedia claims he's living in Canada as an orthopedic surgeon).
Also notably weird in Gundam vs. Zeta Gundam: the original series and Mobile Suit Zeta Gundam were dubbed by different groups, the game uses both groups for their specific storylines, and there's a What If? route that is, basically, the events of the first in the timeline of the second. Meaning returning characters will switch voices on the fly, depending on what's happening.
In the Broken Sword series the main character George Stobbart's voice is always Rolf Saxon. But Nicole Collard, the second main character in most of them, has been voiced by a different actress in each game: Hazel Ellerby in "The Shadow of the Templars" (also known as "Circle of Blood"), Flaminia Cinque in "The Smoking Mirror", Sarah Crook in "The Sleeping Dragon" and Katherine Pageon in "The Angel of Death" (also known as "Secrets of the Ark").
Kasumi was first voiced by Sakura Tange. From Dead Or Alive 3 onwards, she is voiced by Houko Kuwashima - although Dead Or Alive Ultimate 2 had the option to choose between Tange and Kuwashima.
Tina also had a different VA in the first game before her current actress Yuko Nagashima took over. Bayman was voiced by Hisao Egawa in the first two games and by Banjo Ginga in all the following ones. Dimensions had numerous replacements, notably seeing Jann Lee, Brad Wong, Raidou, Leon, Bass, and Gen Fu all recast with new voice actors (though in the latter three examples, it's justified as their original voice actors tragically passed away before recording for the new game).
On the English side of things, almost all of the characters returning for Dead or Alive 5 from DOA Dimensionsnote the first mainline DOA entry since DOA 2: Hardcore to be dubbed in English had different voice actors, with the only exceptions being Ryu Hayabusa (Troy Bakernote who also replaced Ninja Gaiden II's voice actor as Hayabusa for NGIII), Hayate (Yuri Lowenthal), Hitomi (Eden Riegel) and Brad Wong (Grant George).
Between Dragon Age: Origins and Dragon Age II, a few characters were recast. Victoria Kruger replaced Mika Simmons as Isabela, because there were concerns about the vocal similarity between Isabela and Queen Anora being too obvious with Isabela in a more major role. Adam Howden replaced Greg Ellis as Anders because Ellis couldn't commit to the recording schedule for such a major character. Merrill was a bit part in the first game voiced by Erin Matthews, and when she became a full party member for Dragon Age II, she was recast with Eve Myles.
In Batman Arkham City, Tara Strong replaces Arleen Sorkin as the voice of Harley Quinn and David Kaye replaces Tom Kane as Commissioner Gordon.
The first expansion pack for First Encounter Assault Recon has a brief section where you meet up with Norton Mapes again, who has a different voice actor than he did in the base game. What makes this especially odd is that the other major returning characters (Holiday, Jin, and Fettel) all kept their original voice actors, and the second expansion managed to bring back Commissioner Betters' actor as well (his only lines in Extraction Point were re-used from the original).
Between Rainbow Six: Vegas 1 and 2, every voice actor except for Jung Park's was replaced. Michael Walters is the only other returning character who really sounds anything like he originally did, by way of having the only new actor who bothered retaining the character's distinctive accent - most notably, Logan Keller's Texan accent in the first game disappears entirely in the day or so between its missions and the final one of the second.
Likewise, Fuuka Yamagishi has her voice actress from Persona 3 (at the time of this writing, unkwnown. Possibly Paula Tiso) replaced by another (who is also, at the time of this writing, unknown. Probably Wendee Lee).
Midway replaced half of the digitized actors from the first two Mortal Kombat games in Mortal Kombat 3. The only ones who returned were Tony Marquez (Kung Lao), Richard Divizio (Kano, Baraka and Kabal), John Parrish (Jax) and Brian Glynn (Shao Kahn).
Eddie Wong replaced Ho Sung Pak as Liu Kang.
Kerri Hoskins replaced Elizabeth Malecki as Sonya Blade.
John Turk replaced Phillip Ahn as Shang Tsung and Daniel Pesina as Sub-Zero. Turk would go on to play all of the masked ninjas in Ultimate Mortal Kombat 3 as well.
In Ultimate, Becky Gable was brought in to replace Katalin Zamiar as the female ninjas (Kitana, Mileena and Jade).
Johnny Cage would be the last character whose actor was replaced. Originally, Midway was planning to leave him out of Mortal Kombat Trilogy due to the Creator Backlash that resulted when Dan Pesina posed in character as Cage for an ad for BloodStorm. But then they decided to bring Cage by replacing Dan Pesina with Chris Alexander.
In the Japanese version of the Pokémon anime, Bianca is voiced by Shizuka Ito; in the trailer for Pokémon Black 2 and White 2, however, she is voiced by Ayana Taketatsu. This also happened in English: Bianca is voiced in the anime by Erica Schroeder/Bella Hudson, but in the trailer by Eileen Stevens. It's most likely because the aforementioned trailer and anime series are created by seperate teams.
Most of the returning characters from the first Dawn of War got new voice actors in DOWII. This is given an in-story justification for the characters of the Blood Ravens chapter, as one of their geneseed mutations is said to occasionally cause replication errors in the cells of their vocal cords that lead to their voices changing every few years. Eliphas the Inheritor, a member of a completely different Space Marine legion also gets a new VA, but this may be excused by the fact that he's been killed and brought back in a new body.
Beat from Jet Set Radio does not have any of his original voice actors in the Sega Superstars series. Instead, he has a voice that sounds like a 12-year-old boy (even in All-Stars Racing, in which he appears in his Future incarnation, who is older, but yet he still sounds like he's 12!).
On the topic of Sega Superstars/All-Stars, Wreck-It Ralph has a replacement VA in All-Stars Racing Transformed, because it would've cost too much to get John C. Reiley (most of the time, game developers cannot afford big-name actors, but there have been a few exceptions). Also, Pyro, Heavy, and Spy (exclusive to the PC version) sound different too.
Perfect Dark: Joanna Dark's voice actress switched from Eveline Fischer in the original, to Laurence Bouvard in the prequel, also contributing to the loss of her accent (The former actress is British, the latter is American).
In the first Call of Duty: Black Ops, Jason Hudson was played by Ed Harris. However, for Black Ops II, he was replaced by Michael Keaton. Doesn't sound too bad on paper, but Keaton's voice is considerably less deep and gravelly than Harris's, and since the character was supposed to be 20 years older in the second game, the transition is quite rough.
Black Ops has a single-game example in John F. Kennedy - in the singleplayer mission "U.S.D.D." he is voiced by Chriss Anglin, who attempts to realistically mimic JFK's voice, while in the Zombies level "Five" he's voiced by Jim Meskimen, who goes the So Bad, It's Good route of the stereotypical, comedic exaggeration of JFK's voice.
Modern Warfare 3 replaced the actors for Overlord and MacMillan, though that can be justified (someone new could have taken over as "Overlord Actual" between the two games, and MacMillan is twenty years older than he was when we last saw him). Less justifiably, Nikolai's actor has also been replaced.
In Dark Seed Mike Dawson is portrayed by the creator of the same name, Mike Dawson. In the sequel, Mike is portrayed by Chris Gilbert and apart from the wardrobe, there's almost no similarity between the two.
007: From Russia with Love recast almost the entire film, due largely to the fact that the game was made forty-odd years later and, for example, Bernard Lee (M) died in 1981. However, the game traded itself in part on the fact that Sean Connery was convinced to voice James Bond, reprising the role for the first time since Never Say Never Again.
Borderlands 2 replaced the voice actors for both Roland and Moredcai. Roland went from sounding less like Unreal Tournament 3's version of Malcolm (complete with gangsta-isms) who took everything not very seriously, to a very straight-faced leader-sounding sort of person. Mordecai was given an accent and a bit of a slur.
Ace Attorney: From the first through the fourth games in the series, Phoenix Wright was "voiced" (in "Objection!" shouts and the like) by Capcom producer Ben Judd. For both Ultimate Marvel vs. Capcom 3 and Dual Destinies (where the character has actual lines), the part went to Sam Riegel.