And more along that line, Pre-Crisis Supergirl. She managed to bust the armor of a heretofore-untouchable universe-eating dark god, though he took her out soon after, she still managed to force it to flee into the darker corners of the multiverse.
Skurge the Executioner's last stand against the forces of Hela in Thor # 362. This one is particularly notable in that unlike everyone else in this section, he actually stayed dead. (Though his after-death exploits eventually moved him from Hel to Valhalla.)
"They sing no songs in Hel, nor do they celebrate heroes... ...For silent is that dismal realm and cheerless... ...But the story of the Gjallerbru and the god who defended it is whispered across the nine worlds... ...And when a new arrival asks about the one to whom even Hela bows her head... ...The answer is always the same... He stood alone at Gjallerbru...
Colossus: After a years-long Trauma Conga Line, injected himself with a vaccine for the Legacy Virus which he knew would kill him, but cure everyone else on Earth infected with the disease.
Magneto: After a trip through the Heel-Face Revolving Door and a Treacherous Advisor stabbing him in the back, simultaneously shut down every nuclear weapon on board his orbital base before it could detonate and guided said base to burn up in the Earth's atmosphere with himself and some loyal Acolytes on board, while at the same time sending Xavier a telepathic Final Speech.
Harry Leland of the Hellfire Club, having suffered a heart attack in a joint Hellfire and X-Men battle against Nimrod, Sentinel from the Future, used his last energy to drop Sebastian Shaw on Nimrod. Wolverine commented, "Fat man had his faults ... but he made his exit with style."
Nightcrawler in the Second Coming arc. He bamfs in around Bastion's arm, keeping him from killing Hope, then teleports halfway across the country (in every other instance about five miles has been his range limit) on the strength from a single whispered prayer. He then dumps Hope right at Cyclops' feet, Bastion's arm still sticking from his chest, and only allows himself to die once he knows Hope is safe.
Pyro, a frequent Brotherhood mook and antagonist to the X-Men, went out rescuing Senator Kelly from an assassination attempt while in the process of dying from the legacy virus. He tore through his former compatriots like a knife through butter, and succumbed to the legacy virus in the senator's arms, begging him to change his views on human-mutant relations to prevent an upcoming war. It worked. Unfortunately, Kelly was assassinated shortly later by a group of humans for changing his stance towards mutants.
Thor # 343: Eilif the Lost, last survivor of a Viking Lost Colony, aided Thor against a dragon Mjolnir couldn't harm. Wounded, feeling his energy failing, he climbed to a position above the dragon and dived onto it with his spear. "The son... of Odin... must not... perish... because Eilif... failed in his duty!" Eilif didn't realize it, but Odin had earlier put a special blessing on the spear, and it pierced the dragon's hide. Then Thor hammered it into the heart.
"Eilif! Eilif! Has the life fled your shattered body? Can you no longer hear even the voices of the gods?"
For a fry cook from Oklahoma, Bill, Born of Bills went out like a badass. Not only did he manage to reveal a plot against the Aesir to Balder with his dying breath, he got the chance to save the prince from a sneak shot with the last of his strength in the same scene. And then he got a Viking funeral. Given by fucking gods.
He was last seen eating with the honored fallen in Valhalla (asking if there was any mayo). And, very recently, greeting the love of his life when she joined him there.
Through much of his history, Eddie Bloomberg, aka Kid Devil had been an underdog, often feeling incompetent and afraid that he wasn't good enough for the Teen Titans, who had become his surrogate family. Things got better after he got a new power and changed his name to Red Devil, but got worse again once he lost his powers. Did that stop him from being the hero he dreamed of becoming? No. During an attack and jailbreak on the city caused by the new Fearsome Five, Eddie saved all of San Fransisco by taking a dying metahuman who would blow up like a nuke on board the Titans jet and flying it high above Earth where they detonated safely. Most Titans' deaths have been pretty lame, but Eddie went out doing the most heroic thing he'd ever done in his life, finally realizing his dream.
During Grant Morrison's run on Justice League of America, the story envisioned a dark future where Darkseid had taken over Earth. Third-tier hero Aztek was a survivor, and in a last-ditch effort, was sent to shut down the slave device power generators Darkseid had built on the moon. Surrounded and beaten, he whispered to his dying teammate: My armor's powered by a four-dimensional battery, yeah? The only thing that stops the energy from erupting into 3-D space with a destructive force greater than any weapon known on Earth... is a little fader switch on my belt. And guess what I just did.And boom went the moon.
Captain Marvel in Kingdom Come managed to end the Metahuman war and gave the Metahumans a chance of survival in one Crowning Moment Of Awesome by grabbing a huge bomb flying towards the battle and detonate it high over the ground with his magic lightning bolts.
Captain Marvel:Shazam! Shazam! SHAZAAM!
A rare villainous example with The Joker in Batman: The Dark Knight Returns. Who, after being crippled by Batman, SNAPS HIS OWN NECK BY TWISTING IT AROUND to frame his nemesis, and then dies laughing.
Batman then invokes this trope by fighting Superman to a standstill before dying of a heart attack.
G.I. Joe. Yes, in the comics, Joes die. During the second invasion of Cobra Island a sabotage team sets the bombs around the aircraft destroying device. Flash and Mainframe are separated and held at gunpoint. "Mission accomplished." they growl to the Cobra soldiers. BOOM. You won't see that in the cartoons.
Admittedly, it wasn't glorious, or flashy, but Steve Rogers' death during Civil War definitely counts. He died pushing someone else out of the way of a bullet—sure, the first bullet didn't kill him, but the Heroic Sacrifice after all that he had been through lately, just because he still cared about America and the people in it...
During the Avengers Disassembled story arc Hawkeye's quiver of explosive arrows was hit and set on fire. He then grabs a near by Kree solder and rides his jet pack into the Kree battleship's engine taking it out with him.
Hawkeye: NOT LIKE THIS! NOT LIKE THIS! LIKE THIS!
Johnny Storm's demise. He stayed behind in the Negative Zone to keep the portal sealed off. As Annihlus' army came down upon him, Johnny gave one of the most badass Last Stand's in comic history:
Human Torch: "A billion to one? You think I'm afraid of that? YOU THINK I'M AFRAID OF THAT?! FLAME ON!"
The current page image, from DC: The New Frontier. Yes, that is a Badass Normal jumping into a T-Rex's mouth with a live hand grenade in each hand, and it is awesome.
The death of Ultimate Spiderman in the aptly named "The Death of Spider-man" arc certainly applies. For starters he jumps in front of a bullet for Captain America without a moment's thought, shows up to fight the Sinister Six still wounded and doesn't stop fighting until he's taken them all out and uses his last ounce of strength to hit the Green Goblin with a semi-truck to protect Aunt May.
The character may be an extremely minor one, but an issue of Daredevil gives a mobster a great DMOA. He delivers an epic "The Reason You Suck" Speech to his former boss The Kingpin (who is holding him at gunpoint), the final words of which are "L'chaim, fatass!"
Thor's death in Fear Itself. He takes out the Serpent and stops Ragnarok.
Adult Loki: No, I will change - Kid Loki: No, of course you won't. They won't let you. I played and won. I changed. You're just being yourself, as always. I won and you lost. Never forget it. I win.
In Amazing Spider-Man #700, Peter is trapped in Otto Octavious's dying body, and had attempted to undo the Grand Theft Me Otto pulled on him, but it backfired, and Otto is prepared to finish him off. However, both of them simultaneously have a memory of Uncle Ben, and Peter realises that the Octobot that he tried to switch minds with has given him a link to Otto's mind, and uses it to his advantage, bombarding Otto with memories of Peter's trials and tribulations. Otto finally understands that with Peter's great power Comes Great Responsibility, and promises Peter that he'll protect his friends and family, and continue Spider-Man's legacy. Peter finally expires, but he had left his world not to a villain, but to the Superior Spider-Man.
Transmetropolitan: Fred Christ leads a group of Transients in a public protest against a massive crush of police. One of them promptly informs Fred that there are no cameras - nobody is watching. Fred briefly goes silent, realizing that he and the rest of the group are dead, and then gives a simple reply: "Rush them!" He leads the charge, and is first to fall.
Damian Wayne's death. He entered the Batman franchise a whiny murderous entitled brat and exits it as true a hero as any other member of the Bat-family. He puts up a valiant but futile fight against his own monstrous clone Heretic to protect a girl. Damian refuses to give up even after being riddled with bullets and arrows and having his back broken by Heretic. Right to the very end, up to the moment Heretic impales him with a sword, Damian also tries to reach out to his mother Talia one last time. Damian was raised to be a tyrant but died a hero.
In the final issue of Godzilla Ongoing, Boxer throws himself into Godzilla's mouth.
Manitou Raven's death in the middle of Justice League Elite. In the middle of a mission that's gone south, he literally sees Death (in the form of the Black Racer) coming for his buddy Major Disaster, whose usually-formidable powers happen to be crapping out because of his alcoholism. Manitou doesn't even hesitate. He uses his magic word to turn into a giant and takes the full brunt of the Black Racer's attack.
Considering Xadhoom was a walking CHARACTER of awesome,her death could only be just as epic.After saving her people,who had been enslaved for years by the Evronians,with the help of Paperinik and Xari,they realize they'll need a new planet to settle on,since the closest one is too poor of energy to live on.So Xadhoom(who is basically a star in humanoid form)kill herself to become a sun and assure her people's survival.And yet she still menages to be awesome after her death.