Shiro's death from Death Masks, which is also a Tear Jerker. Giving himself to Nicodemus, knowing it would be his death, to save Harry's life. He holds up against the torture of the Denarians and gives his friends key advice to save them.
It gets better as Shiro had basically met Harry a day or two prior to this. Thats right, he sacrifices himself to a horrific fate to protect the man he barely knows (although, having Michael vouch for Harry was probably enough).
And his final act as a Knight was to entrust Harry with his sword to find the right person for it. Harry waited five years before his instincts told him he found the man: Nicodemus himself. By offering him the sword in a deal, it stroked Nicodemus' ego and hit his fear at the Knights always screwing with his plans. It also was the only way Harry was going to save a little girl and the world from Nicodemus' plot. Nicodemus accepts the deal and this action leads to his defeat once more. Harry wondered if Shiro knew this day would come and that action five years ago ended up saving the world now.
Mortally-wounded Carmichael gets one by leaping on the loup-garou's back in Fool Moon, saving Murphy's life.
In Changes after becoming a full vampire, Susan allows herself to be sacrificed by Harry to activate a bloodline curse destroying the Red Court and saving their daughter from their clutches.
Also in Changes Martin played the role of traitor to anger Susan enough so she would kill him and turn into a full vampire and set Harry up to be there so Harry could destroy the Red Court as part of a long gambit.
Dune: Duncan Idaho fits in here somewhere. Ditto Duke Leto.
Duncan Idaho held off the Emperor's Sardaukar, hardened prisoners who survived training on a hellish prison planet, giving time for Paul and Jessica Atreides to escape. As a comparison, a single Sardaukar was considered one of the best soldiers in the Imperium. Duncan killed seventeen, single-handedly. The Sardaukar were suitably impressed, and saved his genetic material to be cloned.
Dr. Yueh. Forced to betray his lord (Duke Leto) to the Harkonnens by their threat to his wife, and backstabbed after his task was done. "You will join her, as I promised" (in death). This was no surprise; his counterplot (implanting a poison gas tooth in the paralyzed Leto) came within a breath of killing Baron Vladimir Harkonnen in the act of gloating.
Moby-Dick: "Towards thee I roll, thou all-destroying but unconquering whale; to the last I grapple with thee; from hell's heart I stab at thee; for hate's sake I spit my last breath at thee!" More a Badass Boast, but still...
Also, Jesus Christ. Not only dying for the sins of others, but forgiving those who executed Him. He came back (according to the resurrection), though.
Jesus: Forgive them, they know not what they do.
Not only that, but his death caused the veil in the temple to split, the earth to crack, the sky to go dark, a hurricane, and a whole bunch of corpses to start walking around.
Alongside Jesus are the disciples. Peter asks to get crucified upside down, putting himself above them in power. Paul exercises his right as a Roman citizen to a speedy execution and gets beheaded.
Malazan Book of the Fallen has Anomander Rake, who sacrifices himself to convince the goddess of his people to return by allowing himself to be killed by his own sword so that his spirit enters the Pocket Dimension inside, where said goddess is kept.
The Vong are massive xenophobes, they consider anything not Vong to be evil, wrong, and unworthy of anything but destruction. Some time after this, a character claims to have seen in a vision, a new god was added to the Vong pantheon. Called the Ganner, it is the giant who guards the gates to the afterlife, armed with a blazing sword, above which were etched the words "None Shall Pass"...in the Basic galactic tongue.
Chewbacca's death in Vector Prime, the first novel of the series. Han, Chewie and Anakin Solo were on the planet Sernpidal doing Lando a favor when the still hidden Yuuzhan Vong used a gravity manipulating creature to pull one of the planet's moons out of orbit. As the celestial body spiraled ever closer, Han used the Millennium Falcon to gather as many refugees as possible before taking off. Anakin handed a young child off to Chewbacca and the two made their way back to the Falcon, but Anakin was cracked across the head by a stone kicked up by the storms. Chewbacca looked back after putting the child aboard the Falcon, saw Anakin and raced back for him. He tossed the young man up to the refugees, but the violent atmospheric conditions and the crowding aboard the ship made it impossible for them to get him aboard. At the last moment, the recovered Anakin flew the Falcon away from Sernpidal and Chewbacca's final act was to roar defiantly at the moon as it collided with the planet.
T3-M4's death in Revan. Upon seeing the Sith Emperor, a borderline Eldritch Abomination given human form who's nigh-invincible, about to kill Revan, T3 valiantly charges into battle and blasts the Emperor with a freaking flamethrower. The Sith Emperor responds by vaporizing the poor droid in front of the horrified Revan, but the sheer fact that a little utility droid had the balls to do something like that earns him a place on this page.
In Feist's Riftwar books, this tends to vary wildly between being played completely straight and subverted as brutally as possible. In Darkness at Sethanon, Roland goes down holding off moredhel pursuers. During the Serpentwar, Jimmy and Gamina die in the explosion the former triggered to take down the enemy army, and in Krondor: The Betrayal, Gorath is killed in his effort to prevent the activation of the Lifestone. Yet on the other end of the spectrum, in the Serpentwar you also have PrinceArutha conDoin dying from a broken hip after falling down the stairs, Owen Greylock being killed by a freak shot from a still loaded crossbow at camp, and in Rides a Dread Legion we have Caleb randomly crushed by a collapsed building and Miranda dying of a torn throat after being snuck up on by a random demon. Plenty of characters (including Arutha, of the above examples) die off-panel or just fade into presumed death by old age as the years pass.
David Gemmell's first novel, Legend, is about an aging warrior who deliberately goes looking for a Dying Moment of Awesome. Druss goes down atop a pile of enemy corpses, killed as much by poison as by his wounds. His last act is to throw his axe to kill the one man who dares to mock him.
Oberyn Martell. Tragic in that he did not realize that it would coincide so swiftly with his death; it seems at first like a plain ol' Crowning Moment Of Awesome.
Syrio Forel, while strongly implied, is never explicitly stated to be dead. To give Arya time to escape, he kills or incapacitates five armed soldiers, with a wooden sword and no armour. He still faces a knight of the Kingsguard in full armour, and holds his own until his opponent breaks his stick-sword. We don't see the rest, but in the TV series we hear sounds of serious fighting carry on for some time.
"I am Syrio Forel, and you will now be speaking to me with more respect."
Donal Noye, the one-armed blacksmith who kills THE GODDAMN KING OF GIANTS trying to get through the tunnel through the Wall, blocking it for the rest of the battle, at the cost of his own life. Sadly, we don't get to see exactly what happened, but it was clearly epic.
"If you ever meet a Malkieri, you tell him Jain Farstrider died clean."
None come close to Egwene Al'Vere, the Flame of Tar Valon, the Amyrlin, though: Improvising a new weave which is the antithesis of balefire and using it to destroy some 200 enemy channelers (and (possibly) somewhat stablizing the world that was unraveling from too much balefire).
The Saganami Island Academy, from the Honor Harrington series, is named for Edward Saganami, who attacked several ships he couldn't possibly destroy to give the convoy he was escorting a chance to escape. The records of his final battle are shown at academy graduations, to show the new officers the tradition they're meant to uphold. "Ladies and gentlement - the tradition lives!"
There's also Jack McBryde's death near the end of Torch Of Freedom, taking out Isabelle Bardasano, a crucial Mesan Alignment research facility, and the bulk of the Alignment's security database while ensuring that Anton Zilwicki and Victor Cachat escape with Herlander Simões and his vital information on the Alignment.
And Lara, from the same book: when an assasin releases a neurotoxin gas into the room, she picks up Berry and throws her bodily out into the corridor on the other side of an airtight door, but gets caught in the gas as the door closes. She does her job, and saves her queen, but dies doing it.
From the previous book in that spinoff, Princess Ruth's entire bodyguard detail, though special mention goes to Ahmed Griggs, who after already being fatally wounded, regains consciousness for about thirty seconds, and, dazed, and suffering from serious blood loss, and pain, manages to kill the leader of the attacking group, with his off hand.
No Grayson armsman will settle for anything less. Every time a Grayson armsman dies it is in the line of duty and, often as not, a Heroic Sacrifice to boot.
During the escape from the Tepes, several characters sacrifice themselves in awesome ways, but points go to Andreas Venizoles, a naval officer who decides that the only way to guarantee everyone else makes it out okay is to stop running and cover the retreat, knowing that there will be no escape if he does.
Charles Beckendorf dies in a magical explosion to destroy Kronos' ship, the Princess Andromeda.
Silena Beauregard dies fighting a drakon after bringing the Ares cabin into battle.
Luke Castellan kills himself to destroy Kronos.
Bianca Di Angelo blows up a model of Talos, with her still inside it
Zoe Nightshade takes a blow for Artemis
Arnold J. Rimmer from Last Human by Doug Naylor. Arnold, when he realizes that he's a goner from being mortally wounded, decides to fly into malevolent SHIT-storm, and saves everyone elses life. Which is huge considering his nobility track record.
Major Brant from Stormcaller. One man, no powers, against an army just to buy time for Isak to eradicate with a massive lightning storm. He gets to where Isak is by threatening to kill the court wizards unless they launch him up there. He dies holding off two opponents at once. By being consumed by a massive lightning bolt. Bad Ass.
Colonel Adler was a subversion. After reluctantly following his superior General Lang's orders to abandon a group of civilians to almost certain death, he planned to visit the general in his office and then shoot him, knowing that he would be immediately gunned down. To his frustration, Lang had already killed himself by the time Adler returned.
HMS Thunderchild in The War of the Worlds. Only three Martian warmachines are destroyed in the book, and it is responsible for two. That it has never appeared in any of the movie adaptions of the book is a travesty.
It did in War of the Servers, but I don't think it managed to bring any of the tripods down there...
IIRC, it took down one, and was essential for the escape of the refugees.
It does in Jeff Wayne's Musical Version of The War of the Worlds. HMS Thunderchild gets Crowning Music of Awesome. However, it only accounts for one Martian.
It also appears in Timothy Hines' 2005 War of the Worlds film, and it actually takes down all three Martian walkers blocking the evacuation route before sinking.
Cohen the Barbarian and The Silver Horde in Terry Pratchett's The Last Hero. When they realize that blowing up the Home Of The Gods will destroy the magic that holds the Discworld together, they get it off the mountain ... the fastest way they can.
And Snape dies performing the crucial act that will show Harry what he has to do to save the entire Wizarding world (giving him his memories).
An often overlooked example: Regulus Black, upon figuring out that Voldemort has created a horcrux, convinces Kreacher to take him to the horcrux cave, drinks every last drop of the poison in the bowl(most likely without aid, a feat even Dumbledore couldn't manage), and is pulled underwater and killed by inferi while yelling for Kreacher to switch the lockets and get out of there. He even leaves a mocking note for Voldemort.
James and Lily Potter, especially Lily who in essence was the whole reason Harry survived to defeat Voldemort.
Harry himself, who is still a child and who in spite of his fear walks toward rather than away from his death, with no knowledge that it won't be final.
King Haarahld Ahrmahk of Safehold got this at the end of the first book, Off Armageddon Reef. In a pitched naval battle, he begins chasing down fleeing enemy ships, knowing they have to make their victory as total as possible. When the last of those ships turns around for a suicide run, Haarahld fights alongside his men, and dies in the act of saving an eleven year old midshipman who was trying to take a crossbow bolt meant for Haarahld. This act makes him a hero to his people and, when a squadron has to make a similar sacrifice in A Mighty Fortress they use "Remember King Haarahld" as their battle cry.
Also in A Mighty Fortress, Hauwerd Wylsynn, knowing the Inquisition is about to move against him and his brother, whose crimes were trying to reform the Corrupt Church, decides it's better to be killed than be tortured to death and fights with the Temple Guardsmen sent to arrest him. It is worth noting that Hauwerd Wylsynn, before becoming a Vicar, was a former Temple Guardsman. He takes down four younger, armed, and armored men before finally being cut down. The Guards who watched the fight knew they would remember it as surely as they would be banned from speaking of it.
The second book, By Schism Rent Asunder, former Archbishop of Charis Erayk Dynnys is facing execution as a scapegoat for Charis' rebellion against Mother Church. He's given the opportunity for a quick and easy death if he will publicly endorse the Church's version of events. To the surprise of many, especially the Inquisition, Dynnys uses his final words to denounce the Church's reasons for attacking Charis for the lies they were. An act of bravery that ultimately caused Dynnys to endure several hours of horrific torture before finally being allowed to die.
In the fifth book another character pulls off a similar moment, having already been brutally tortured and having had his tongue cut out, when asked if he has any last words by the one presiding over his execution, he spits in their face.
Finally, Prince Hektor manages a Dying Moment of Heartwarming in By Heresies Distressed. When he and the Crown Prince, who had until then been Hektor's Unfavorite, are attacked by assassins, Hektor realizes in his very final moments that he does and always did love his son.
Another example from a David Weber book, Crown Prince Janaki Calirath spends over a day constantly seeing a vision of how he was going to die, experiencing the pain of it nearly continually, in order to Glimpse his enemies' plans of attack before they actually happened, and give his side the edge they needed to win. And just before he dies, he still has the presence of mind to throw the only other person on the tower with him out of the way of the griffin that kills him.
Ellidyr, spending most of The Black Cauldron being a grade-A Jerkass all the way up to betraying the heroes, finally realizes the error of his ways... and uses his Redemption Equals Death moment to fight his way past numerous enemies to jump into the titular cauldron, knowing that doing so will kill him but will also break the cauldron and put a stop to one of the Big Bad's most effective weapons.
Paul/Pwyll Twiceborn in Guy Gavriel Kay's The Fionavar Tapestry. He dies after spending several days in agony, crucified in a sacred glade, with what appear to be Odin's ravens tormenting him with his past. He sacrifices himself willingly in place of the King to end a devastating drought, forgives himself for his accidental part in the death of his wife, and finally comes to terms with her death, crying for the first time. He dies in the first rain the land has seen in far too long.
It's arguable that Paul is just the first. Diarmuid, Kevin, Finn, Darien... everybody who dies in here gets an awesome death. Most of them are also Tear Jerker material.
Wulfgar the Barbarian in The Legacy has one of these. He is being bitten by a Yochlol (think 15 foot glob of half melted wax with tentacles and a giant mouth full of large teeth) and is in excruciating pain. Yet, through the pain, he is still smashing the Yochlol with his hammer, and when that doesn't work, he brings the cave ceiling down, killing him and the creature. All this to save the love of his life: Catti-Brie. While singing to his Warrior God, Tempus!
Oh, and before he does, he turns himself into a living metal statue just so that he can charge the Vord lines first. This technique is so difficult that only one other character, himself so badass that it's a wonder he averted this trope himself, ever managed it in the books. Apparently it's also unbearably painful. Oh, and this was after Gaius had spent months being weakened by illness and poison.
Also, High Lord Cereus launches himself into the mouth of a Vordbulk, and blows up its head, saving the last defenders of Alera.
Warrior Poet Bobby Shaftoe (fatally wounded, he still manages to fill an enemy fortress with burning oil, then jumps into it "on an impulse" and spends his last living moments composing a death haiku in his head: "Semper Fidelis / Dawn star flares on disk of night / I fall, sun rises")
Admiral Yamamoto (who is "on fire and hurtling through the jungle at a hundred miles per hour in a chair, closely pursued by tons of flaming junk" when he realizes that the fact of his imminent death can only mean the Americans have cracked the Japanese military codes - and his last thoughts aren't "Oh Shit" but "I must get word out!".
Anton Dubois in A Dirty Job, trapped in his second-hand book store with three Morrigan out for blood:
Anton: Do you remember what a claymore looks like? ... Well, in this time, a claymore means something else.
This is the preferred method of exit for Spartans. A few examples include the Spartan-IIIs Robert and Shane facing down an army of Covenant after their entire company had been killed; Robert is shot in the stomach by a plasma bolt and as it burns through his armor and flesh he fires his rifle dry. By that point he was in full cardiac arrest but still primed and threw a grenade before dropping. Then Shane, all alone, continued to fire carefully and precisely at the advancing enemy before running out of ammo for his assault rifle and switching to his pistol. Kurt-051, their trainer, achieves the best DMA by standing alone against an advancing Covenant army to buy the rest of his Spartans time to make it through a slipspace portal, then detonating two nuclear warheads.
"Fred" the sentient white hole from the Young Wizards universesacrifices himself by blowing his quanta (releasing the energy of several giant blue-white stars all at once) to provide light that the moon can reflect on to the pages of the Book of Night with Moon, the sacred text that has to be read from to counteract the Dark Book and the forces of the Lone Power.
Ed the Master Shark in Book 2, Deep Wizardry, allows the krakens and the Lone Power to kill him and release his blood into the water, calling every shark in the entire ocean to come in a feeding frenzy and in that feeding frenzy rip the Lone Power to shreds. Ed is a calm, businesslike killer who has never been truly loved by anyone, who finally gained friendship with one of the main characters and in doing so gained the motivation to give his life to keep her and millions of other people alive.
Betty Callahan, Nita's mother, does die at the end of A Wizard's Dilemma, but before doing so, thoroughly stomps on the Lone Power and makes It experience every pain, emotional and physical, that she's ever experienced in her entire life.
Ronan would have done this in Wizards At War, only he gets better.
Well ... Roshaun technically pulled one of these also at the end of Wizards At War, but nobody knows if he's dead. Nobody knows where he is, or if he even physically exists anymore. Argh.
Elven Hunter Crispin in The Elfstones of Shannara. With the rest of his men dead, Crispin holds the Pykon Bridge against The Reaper, while Wil and Amberle, who he is charged with protecting make their escape. The Reaper is an unstoppable killing machine specially bred to be the Demon equivalent of a Serial Killer. It needs to murder on an instinctive level, and on separate occasions waylays and destroys an Elven patrol, and murders twenty soldiers in their beds after breaking into a barracks. Yet Crispin, a Mauve Shirt at best, holds the damn thing off by himself so that his charges can get away, successfully slowing it down in the process. Damn.
What about the death of Garet Jax in The Wishsong of Shannara? Pretty much the best fighter in the whole world, he has a vision of a creature that would be capable of giving him a real battle. That creature, the Jachyra, actually kills Allanon in the middle of the story, who up to that point has been seen as almost invincible. At that time, Allanon mentions that only magic could destroy the Jachyra. So what does Garet Jax do when he confronts it at the end? Fights it one-on-one and wins, with only his sword and the power of sheer Badassery. And then dies of his wounds immediately after.
Wolf in The Talisman dies by taking out almost the entirety of Sunlight Gardener's institution. There seemed to be no way he would ever be able to leave safely and he was slowly dying, so he took on dozens of guards barehanded and killed them all.
The title character in Damon Runyon's short story "Earthquake" is a very strong criminal who flees to South America after accidentally killing a cop. Tough cop Brannigan tracks him down, but as he is about to arrest him a strong earth tremor shakes the little town and nearly collapses the orphanage. Earthquake props the door-lintel up so that Brannigan can arrange for the survivors to be rescued, but there is no way to get him out. However, he has time to tell Brannigan that he knew what he was doing before he stepped into the breach, and this is his way of making up for killing the cop. Another earth tremor then finishes him off mercifully.
Beowulf goes out in a manner befitting a legendary warrior and epic badass. As an old man (quite some time after his defeats of Grendel and Grendel's mother) his people are menaced by a dragon. Beowulf goes out alone to fight it, and although he ends up needing a little help from one of his warriors, he takes the dragon down. He dies short while after the battle and is buried with the dragon's hoard.
In Matter, this applies to Djan Seriy Anaplian, and her brother Ferbin. Ferbin sacrifices himself to satisfy the Iln's curiosity, so that his sister can get close enough to detonate her implanted antimatter reactor. And this is to stop the Iln from destroying a highly populated Shellworld.
Jean Prouvaire, a quiet poet who liked flowers, was shot shouting, "Long live France! Long live the future!"
In Neuromancer, the Dixie Flatline's construct can't exactly die, being an interactive record of his personality, but it is destroyed during the novel's climax, punching through Tessier-Ashpool's computer defenses. T-A's setup used their shackled AI for security and was explicitly stated to be the best in the world. Breaking an AI's defenses had previously been considered completely impossible for a human "cowboy".
In the final Night Lords novel Void Stalker by Aaron Dembski-Bowden the main character Talos Valcoran dies awesomely. His entire company has been wiped out by the Phoenix Lord Jain Zar and he has accepted that even if he survives, he will die in a few years from gene-seed rejection. He calmly says goodbye to the only other, conscious, survivor and says that their debt is cleared. He then waits for the Phoenix Lord to arrive and as she impales him, he detonates every single grenade he has to kill them both. He perishes in the explosion and Jain Zar is left crippled and completely burnt.
And then Malcharion comes in and steps on her just before he dies himself.
Fingolfin, High-King of the Noldor, challenges Morgoth, God of Evil, to a duel; he manages to wound the bastard seven times before he's beaten down, and as Morgoth steps on him, with his last breath he slices Morgoth's foot so badly that the God of Evil is crippled forever.
Azaghâl the Dwarf-King, who was crushed by Glaurung the Father of Dragons, with his dying breath drove his knife into the dragon's belly and sent him routing off the field in mid-battle; and saved everyone else on his side of the line.
Fëanor, High King of the Noldor, stated in canon to be the single most clever, skilled and strongest elf ever, goes down after routing an army of orcs that caught his troops by surprise and KEEPING them routed essentially alone for hours, after which Morgoth decides enough is enough and sends out the balrogs. Case closed right? WRONG. They STILL can't kill him, even though ALL of the balrogs(not just the measly one that Gandalf fought) are ganging up on him and he is on FIRE. So he has to send out the balrog equivalant of Sauron to kill him..... and he STILL doesn't die, he manages to fight on alone until his son's and their army show up. He dies of full body burns and injuries a few hours later, when his spirit is so fiery that it immolates his corpse on the way out. If thats not a Dying moment of Awesome then I don't know what is.
Finrod Feaguland in an effort to save Beren, breaks free of his bonds and kills a werewolf with his bare hands and teeth.
"Having taken some medicine supplied by his Wicked Aunt and feeling his strength going, he blew a dying blast on his horn and with his dying breath fired a last shot out of his bedroom window, and hit the Sheriff of Nottingham again."