Awesome Music: Many people consider cover songs better than the original songs. Most YouTube videos of them will have people stating that or how their cover of it made people like the original song in the comments.
Base-Breaking Character: Dave Seville is either a kind hearted man who loves his family but gives them tough love or an annoying father who treats them like garbage.
Covered Up: Ross Bagdasarian did this to himself regarding "Witch Doctor", as the Chipmunk version of the song has become much more well known than the original version of his 1958 hit single.
Crack Pairing: Crack pairings go through many different phases among the fandom, which almost always ensures a string of fluff fanfics from different authors. Popular phases over the years have included pairing Alvin with Eleanor, Simon with Brittany, Dave with Vinny, and even Alvin with Simon, however, none of them have quite put the "crack" in "crack pairing" as much as Dave and Brittany, with even a few fanfics involving Dave impregnating Brittany.
Epileptic Tree: The Chipmunks and Chipettes grew to human size after coming in contact with the same chemical that mutated the Ninja Turtles (which makes sense, as both series' 80s incarnations were produced by Murakami-Wolf-Swenson, although they only did this series for a few Eps).
Face of the Band: Sort of subverted. Alvin gets a lot of attention, is the lead vocal on 99.9% of the songs they have (for good reason, it's not undeserving), is the star of the show, and was #44 on TV Guide's list of top 50 best cartoon characters of all time. Yet Simon and Theodore are anything but forgotten or put in the background. Each of them have their special and memorable moments in the spotlight, and each have their own fanbases. Theodore's the only one who gets less focused on however, and Simon is second only to Alvin due to their dynamic as brothers. Alvin may be the most publicly recognized, but in-universe (shows, films) there hasn't been an implication of the sort.
Fanon: Charlene was the first Chipette. She appeared in only one song before being replaced with Brittany and her sisters the following year. She has never officially appeared in anything besides her sole song, however fans noticed that an unnamed chipmunk girl in a red dress from The Chipmunks: Rockin' Through the Decades looked a lot like Charlene. Thus, she's considered Charlene and Charlene is never drawn in anything but a rather skimpyred dress. When she appears in fanworks she's usually a long-lost sister or cousin to the Chipettes.
Self-Fanservice: Evident if one were to ever browse through Fan Fiction.Net or deviantART. This is especially true of The Chipettes, moreso than The Chipmunks (though, that's not to say the boys don't have their own fair share). In the case of fan art, many fans age up The Chipettes considerably, giving them an excuse to be drawn with boobs and Hartman Hips. Eleanor, in particular, is drawn much slimmer than she's usually depicted in the franchise, and also has a tendency to be glammed up as well, especially when she's paired with Alvin in the fan work. Brittany also gets glammed a lot, though it's usually more because of how she's already quite a fashionista, and in the case of fanfics, Brittany Really Gets Around, with just about everybody (even her own sisters). Jeanette's fan art usually tends to be just a tad more tasteful, for the most part, but however, fanfiction is an entirely different story: either she's a depraved horndog dying to have one of the boys (mostly Simon) inside her (or even play with Brittany), or a constant rape victim. It also doesn't help that often in fanfiction, the girls' physical appearances and maturity are almost-always explained in very detailed descriptions.
Ship-to-Ship Combat: There is a serious divide among the fandom with canon shippers and mixed shippers. It occasionally even grows to a point where the two groups of shippers practically go to war over why their respective shipping is better, and why the opposing shipping sucks.
Signature Song: Generally, there are two candidates: "The Chipmunk Song (Christmas Don't Be Late)" and "We're the Chipmunks" (the theme tune for the 1980s and 2015 cartoon series).
Toy Ship: The Chipmunks and The Chipettes, who are all about 8-9 years old (though you wouldn't normally tell with the way they act).
The break in "Ragtime Cowboy Joe" had Alvin playing around with a gun. Unthinkable if the song came out in the 21st century.
A minor one in the Japanese dub, but in this version, the relationship between the chipmunks with Dave (at least in the dubs of The Alvin Show and Alvin and the Chipmunks) was changed from Dave being a father figure to a big brother instead. This partly very likely because Dave isn't a chipmunk like them, and, for the time period when the series was released in Japan, an human can't be a father figure for an animal, so the best thing Dave can be for them is being a brother for them. Keep in mind Japanese language is very specific regarding family relationships, especially towards very unusual ones. On the other hand, the dubs of the live-action films retains the same family dynamics from the original English version.
Broken Base: This has increased among much of the Chipmunk fandom in recent years. A large majority of the fan base grew up with this particular series and love it, especially for nostalgia. On the other hand, some fans hate for one of either two reasons, because it focused less on the music (unlike The Alvin Show), or they're sick of Bagdasarian Productions releasing the same handful of episodes on DVD over and over again.
Ensemble Dark Horse: Both Vinny and Uncle Harry seem to get quite a bit of attention from the fandom; the latter seems to stem from the similarities between Harry and "Uncle" Ian from the live-action/CGI films.
"Funny Aneurysm" Moment: In "Thinking Cap Trap", the Chipmunks and Dave appear on a game show. When asked to identify the Bronx Bombers, one of their opponents said they were a New York terrorist group instead of the New York Yankees. This lost its hilarity for obvious reasons after 9/11.
Germans Love David Hasselhoff: This show was popular in the United Kingdom (where it aired on the BBC) and in Canada, where it aired on YTV. Both networks played the show up until 2002.
Growing the Beard: Many credit the 80s series as the height of the franchise, largely for introducing the Chipettes, developing the contemporary designs of the Chipmunks as well as Simon and Theodore's individual personalities. Their stilted speech was also gradually fazed out during the run of the 80s series, making them much better at delivering gags.
Values Dissonance: In the Cinderella dream sequence episode, the Chipettes are shown bathing, seen from the waist up, with nipple dots drawn on. In the 80s no one may have thought much of it but in the modern days with concerns over adults sexualizing & molesting children, more so with the Chipettes looking like little girls, it comes off as a bit disturbing to some viewers. Dorkly Bits was visibly freaked out that the scene even existed when they reviewed inappropriate moments in cartoons. There were also the occasional panty shots of the Chipettes that have the same feel now.
Go figure that these scenes are rather popular with furries, often generating very creepy comments in any Youtube video posting showing them.
In the first film, the two scenes of Dave being woken up by the TV blasting the opening theme to SpongeBob SquarePants were this because those parts were put in unintentionally. They were wrong because it was a Director Allusion, being that Tim Hill worked on SpongeBob in the past.
Digger the Gopher's (as voiced by Eric Bauza) inexplicable cameo in the second movie. There's no build-up to him, nor is he even a side gag. He just happens to appear as a Deus Ex Machina during the climax. Most people don't even know who he is (he's was then-sister company Fox Sports' mascot for NASCAR Racing coverage; he was dropped in 2012 after years of viewer backlash).
Seriously, people had nicer things to say about Transformers: Revenge of the Fallen. For the first movie, it didn't do very well with the critics in the first place, but at least some of them liked it. The reaction was the same for the sequel.
By the time the third one came out, it became almost unanimous that the series had outstayed its welcome, and this hit a tipping point in 2015. To clarify, the third movie did horribly with critics, but was among the highest-grossing films at the time. The critics were quick to make insinuations on what kind of person would actually like such a movie, as reflected in the Rotten Tomatoes consensus:
"Lazy, rote and grating, Chipwrecked is lowest-common-denominator family entertainment that is strictly for the very, very, very young at heart."
Critical Research Failure: Alvin doesn't know the difference between a honey badger and a meerkat in Chipwrecked. Strange, since he and Simon watched Meerkat Manor in a few scenes in The Squeakquel.
The fourth movie fell into Sequelitis since when Fox found themselves without the Star Wars franchise after 35 years and attempted to compete with the now-rival series by releasing the fourth movie the same day The Force Awakens came out, and Road Chip was blasted by critics.
Tainted by the Preview: Some fans who grew up on the 80's cartoon did not gravitate towards the eponymous Chipmunks looking more chipmunk than humanoid, and fans in general were not amused by the poop-eating gag shown in the trailer. Much to the latter's relief, the movie only really had two instances of Toilet Humor.
What an Idiot!: Had Ian played his cards right and learned from the mistakes he made in the first movie, not only would the Chipettes have remained on his side, but he would have most likely won out in the end.
WTH, Casting Agency?: Some felt this way about Justin Long getting cast as the voice of Alvin, since the inevitable voice modulation would make his voice unrecognizable.