and now, the tropical fruit with the carcinogenic peel will bitchslap Peter Morris…
Osiris.
[QUOTE=DocCathode]
The New Mutants- The Beyonder destroyed them, and all memory of them, during Secret Wars II. He later brought them back.
The Wasp?- I can’t remember which hero was killed in Secret Wars. At the time, many of the heros were staying in an alien village. One of the aliens (I believe her name was approximated as Ystaja) had the ability to heal injuries. When the corpse of a hero was found, Ystaja healed her even though it cost her her own life.
QUOTE]
That was secret wars #12 I believe, Dr. Doom stole the Beyonders power, and with the omnipotence that he aquired, killed all the heros with a “bolt from the blue”. Collosus, being only mostly dead, was revived by the healer, who sadly traded her own life for his. Poor Peter knew that it would take a super brain ala Reed Richards to bring the rest of the heros back to life.
If you aren’t going to buy the “Quiver” trade, heres the scoop. But really, you should buy it and read it. Kevin Smith is a little bit better writer than I am, and he had 200 pages filled with pretty artwork to tell this story. If you must know, here it is:
[spoiler]Green Arrow shows up alive, not knowing he’s supposed to be dead, and with no memory of the last 10 years. This really freaks out the JLA. Batman scans him and determines that it’s him, but minus all of the scars and broken bones from the previous 10 years.
He finally gets some aide from the Spectre (Hal Jordan), who takes him, literally, to heaven, where he meets . . . himself, but 10 years older. They have an archery contest and the reincarnated Ollie loses.
What happened was this: Hal missed his friend. Being the wrath of God, literally, he has some influence. He asked Ollie if he’d be willing to come back, but Ollie refused because he liked heaven better than the hell his life had become. The arrived at a solution. Hal could resurrect Green Arrow, but it would be the Green Arrow from the Green Lantern/Green Arrow series, before his life got so screwed up. Thus, the ten year gap. The physical Green Arrow gets sent back as a soulless body, while Ollie’s soul stayed in heaven.
Knowing that he’s a reincarnated body with damaged memories and no soul, and knowing that he’d gone through some pretty awful things, such as killing Hal, his best friend, leads to the reincarnated GA being just as disturbed as he was before he died.
At a critical moment during a battle, the Spectre once again comes to GA’s soul in heaven and asks him to return to his body on earth to help his body. GA reluctantly agrees, and returns to his body just in time to use his superior archery skills to save the day.[/spoiler]
Marvel
The Thing - Possessed by Doom’s spirit, Reed had to off his buddy Ben, then led the FF on a quest to heaven to recover him.
Jack of Hearts - Died in recent Avengers issues, temporarily resurrected in Avengers #500.
Wonder Man - “Killed” once or twice, Simon always manages to come back, as he is a being of pure ionic energy.
The X-Men - Apart from the death empowering Forge’s spell, they had another ‘death’ - they passed through the ‘Siege Perilous’ - a cheesy Deus Ex Machina that reincarnated them. Team at the time included Colossus, Rogue, Storm, Psylocke, and (IIRC) Havok, as well as Wolverine who did not get to pass through the Siege. There were one or two others members, I think, but I can’t recall them at the moment.
Jean Grey - “Died” as a kick-off to the Phoenix Saga, of course. Now dead again.
Quasar - He was killed and had his hands chopped off, poor guy. I forget the circumstances of his resurrection.
Adam Warlock - Marvel’s hardest man in the universe to kill.
Not counting deaths where folks are resurrected two issues later, as part of a weird story arc.
Superman - Died fighting Doomsday.
Wonder Woman - Not aware of her death circumstances, but she did a brief stint as a goddess of Truth before returning to the mortal plane.
Green Arrow - Got blowed up real good. Number Six’s summary is accurate.
Hawkman/Hawkwoman - These two get killed like it was their career. If I recall correctly, the latest was at the hands of Extant in the Zero Hour crossover.
Hal Jordan - Sacrificed himself (after he’d turned villainous and absorbed the power battery on Oa) to save the Earth from the Sun-Eater. Restored to ‘life’ by volunteering as the host of the Spectre during the ‘Day of Judgment’ crossover.
**Metamorpho ** - Already been discussed, but Rex has been “killed” several times over the years, only to reform. In the pages of Sandman, in fact, we see Element Girl, a female counterpart of his, who is unable to kill herself until she entreats Death to let her die. Death comments at one point that the Metamorphs are particularly difficult to kill, but they do die.
Plastic Man - Even though it was part of the JLA-to-the-Past arc, and I’m not counting that death for the rest of the JLA, Plas gets special mention. He was turned to stone and shattered, and the stones were carried all over the globe - and a thousand years later, when the spell was lifted, he returned to ‘flesh’ - still alive.
**Zauriel ** - the JLA’s one-time Angel Ally. Again, it violates my condition, but I add it because it was cool. Zauriel had been stationed on the mortal plane, but needed to get back to Heaven to rally the forces of light against Mageddon. He had one of his earthbound buddies kill him to get back there.
Resurrection Man - Coming back from the dead is his power. He wins the award for most times back from the dead. Similarly…
The Immortal Man - When he dies, he is reincarnated. See also…
Ra’s Al Ghul - His Lazarus pits can restore the dead to life and health.
And of course there are those that died, but made post-mortem cameos, like Barry Allen, Jason Todd, Kara Zor-El… (then, of course, Kara has been apparently restored to the continuity).
CandidGamera, actually, I do plan to buy the TPB, but being as how I’m a spoiler whore from way back, thanks for bringing me up to speed.
Also, “Jason Todd” in “Hush” wasn’t actually Jason Todd. Were the others you mentioned the Real McCoy, or were they just, oh, I don’t know, let’s say Clayface or some other shapeshifter type messin’ with da kids?
Wasn’t counting that Jason Todd appearance, actually. 
Jason made an appearance in the ‘Day of Judgment’ event, while the heroes were passing through Limbo. He also appeared in a Deadman miniseries a couple years back - Deadman was trying to prevent a bad wizard from collecting five heroes’ souls as they died… Barry Allen, Jason Todd, Superman, Hal Jordan were all appearing in a post-mortem capacity.
Barry’s made a bunch of post-mortem appearances - Wally and Max Mercury have been known to commune with the Speed Force and talk to the speedsters who’ve passed beyond; Green Arrow in the aforementioned ‘Quiver’ arc runs into Barry in Heaven; and most complicatedly, Barry spent several years living in the 30th century before he returned to die in the Crisis. Wally’s run into the Barry living there a few times because of time travel.
Kara Zor-El appeared in a Christmas with the Superheroes special, after she’d been officially erased from continuity, interacting with Deadman.
Jason Todd has appeared moe than once as a figment of the imaginations/nightmares of Batman, Nightwing, and Tim Drake. This usually happens when they get a dose of the Scarecrow’s fear gas, causing them to trip out for awhile. Jason’s specter looms large in the Batfamily subconscious. He’s a much better character now, as a psychological device, than he ever was as an independently functioning character.
I remeber an issue of the Avengers where every member of the East Coast and West Coast Avengers was killed in one of the Grandmaster’s contests, except for Cap and Hawkeye. They were returned to life at the end of the issue as a reward for freeing Death from the Grandmaster. I also sort of remember an issue of the X-Men where the whole team was killed (I think) in the Citadel of Light and Shadow, only to be resurrected at the end because Wolverine “passed the test.”
Didn’t Colossus kill himself in order to provide a mutant antibody for that one virus? Isn’t he still supposed to be dead?
Bucky has stayed dead, although, not having read comics in awhile I would not be surprised if those heathens at Marvel brought out a clone or a time-travelling version.
I think Captain Marvel (Mar-vell) is still dead, correct?
Bucky is still dead, as are Gwen Stacy and Ben Parker.
Aunt May died once, but then it turned out it wasn’t Aunt May at all! It was an actress! The real Aunt May had been kidnapped by some villain and held for awhile until they…apparently got bored and gave up. They just decided not to explain it at all. So, so lame.
Marvel
Bucky
Captain Mar-Vell
Jean Grey (at the moment)
The Swordsman (of the Avengers)
DC
Barry Allen (Flash II)
Jim Corrigan (The Spectre I)
Al Pratt (The Atom I)
Kent Nelson (Dr. Fate I)
Wesley Dodds (The Sandman I)
Jason Todd (Robin II)
Hippolyta (Wonder Woman I, technically)
Marvel
Ben Parker
Gwen Stacy (Clones notwithstanding)
Doug Ramsey
Warlock (Douglock, intellectually speaking, wasn’t either one of these guys, as far as we were told, if I recall correctly)
Colossus.
DC
Dr. Midnight (Mid-Nite II)
Wildcat II
Star-Spangled Kid/Skyman
More Back from the Dead:
Galactus.
Does Captain America count as coming back from the dead? I mean the time in “the Avengers” #4 when Sub-Mariner found him frozen in a block of ice and set him free?
Off the top of my head, these Marvel characters were all killed off & were considered dead for a significant time (i.e. longer than a single story-arc) to be revived:
Thor
Iron-Man
Wonder Man (at least twice)
Mr. Fantastic
Dr. Doom
Prof. X
Jean Grey (multiple times again)
Cyclops
the Spider-clone (groan!)
the original Human Torch
Elektra
Guardian (of Alpha Flight)
Sasquatch (ibid)
Hellcat
Angel / Archangel
Blink
Doug Ramsey & Warlock
Jocasta (brought back once, killed & dead for the time being)
Jack of Hearts
Magneto (wonder how long he’ll stay dead THIS time??)
And as far as DC, with all the retcons that’ve taken place, it’s hard to say who hasn’t been killed. But these people haven’t been mentioned -
Artemis (first temporary replacement as Wonder Woman)
Lightning Lad (pre-several reboots)
Raven (of the Teen Titans)
Terra (also of the Teen Titans)
As long as we’re on villans, too, don’t forget Green Goblin I, Norman Osbourne.
Just in case anyone cares: 
Team that provided the life force for Forge’s spell (at the end of Fall of the Mutants): Storm, Wolverine, Colossus, Rogue, Havok, Dazzler, Psylocke, Longshot, and Madelyne Pryor.
Team members who eventually passed through the Siege Perilous: Psylocke, Dazzler, Havok, and Colossus. Rogue had fallen into the Siege months earlier while fighting the combined Nimrod/Master Mold sentinel. Storm was thought to have been killed (accidentally) by Havok while fighting Nanny and the Orphan Maker, and was found later in New Orleans (having been regressed to a pre-pubescent form by Nanny). Longshot had taken off for parts unknown, to “find himself”. Wolverine had also gone off on some solo adventures, returning to find that the rest of the team had gone through the Siege in order to escape the returning Reavers.
Villains, I mean. Soryy, had to correct myself just that once.