Costumed superbeings, whether they be heroes or villains, don't have an easy life. They're constantly fighting, trying to either protect the world from evil or subjugate it, depending on what side of the divide they fall on. There are alien invasions, magical forces attacking, all kinds of infighting and backstabbing. Sometimes, when it comes right down to it, it's much easier to find heroes who haven't died than ones who have.
Of course, a hero who hasn't died isn't any better or worse than one who has. Heroes as powerful and well known as Superman have died, more than once, even. However, not having died is a pretty nice distinction among the super people of the DC Universe.
10 Swamp Thing
Swamp Thing is the avatar of the Green, which represents all plant life on Earth. An elemental, Swamp Thing's powers are pretty amazing and make him one of the most powerful beings on the planet. Even Superman knows better than to mess with Swamp Thing. One of Swamp Thing's best abilities is the power to regrow his body; if he's destroyed, he can make a new body for himself and put his essence into it.
It's pretty much impossible for Swamp Thing to die, making battling him an extremely daunting proposition.
9 Adam Strange
One of the sci-fi heroes of the Silver Age, Adam Strange defends his adopted homeworld of Rann from all manner of threats. Married to the daughter of the planet's leader, Strange is armed with a cool jetpack and laser gun because that was the height of sci-fi comics in the Silver Age. However, even with that scant armament and facing all the threats he has, he's never died.
Strange has survived all kinds of intergalactic conflicts and always came out on top. It's honestly kind of surprising, but he's become a consummate soldier over the years, one who can survive just about anything.
8 Booster Gold
Booster Gold is one of the most annoying heroes ever to join the Justice League. In fact, there's a list of all kinds of negatives associated with the hero from the future, but one of those negatives isn't that he's died. Booster Gold is a much more skilled hero than most people would imagine, and that's kept him out of a lot of trouble over the years.
He has faked his death before, but he's never actually died, which is a pretty big accomplishment for someone who has fought the kind of threats he has; whether it be against the enemies of the Justice League or saving the timestream, Booster Gold does one thing better than mostーsurvives.
7 Shazam
Shazam didn't originate at DC Comics, and at one point, was even more popular than Superman. Eventually, Shazam would be acquired by DC and join the DC Multiverse. One of the most powerful heroes around, Shazam has battled many powerful threats over the years and has always ended up on top, defeating his foes.
This is made all the more impressive when one remembers that Shazam is a young boy in a superpowered titan body. He's never died and has always been at the forefront of the battle against evil.
6 Kyle Rayner
Kyle Rayner became Green Lantern under the worst possible circumstancesーthe Corps was destroyed, and a Parallax possessed Hal Jordan had drained all the power from his vanquished comrades. Rayner was able to defeat him and became the sole Green Lantern in the galaxy for years, using his imagination to create some of the coolest constructs of any Green Lantern.
Rayner went from a guy in a Nine Inch Nails shirt to the bearer of the most powerful weapon in the universe and could survive everything thrown at him. Once the Corps was re-established, he would become one of its most important members, the standard-bearer who kept the Corps alive through some dark years.
5 Mr. Freeze
Mr. Freeze is one of Batman's most tragic villainsーhe only commits crimes to finance his research into curing his wife. Forced to wear armor that keeps him cold and enhances his strength, he uses his freeze ray and scientific know-how to commit all manner of crimes. He's given Batman some pretty good fights over the years, fueled by the desire to save his wife.
Mr. Freeze has never fallen victim to the in-fighting between Gotham's murderous villains, and Batman would never kill him, so Mr. Freeze has never met the reaper.
4 Superboy-Prime
Superboy-Prime is a refugee of the pre-Crisis On Infinite Earths DC Multiverse. Armed with all of the Silver Age Superman's powers, he went a bit crazy witnessing all of the terrible things that happened to the universe. At the same time, he and his fellow multiversal survivors lived in a "paradise" dimension.
Prime would become one of the most dangerous, powerful supervillains around. It's the amazing level of his powers that have kept him alive in all of his battles against some of the most powerful heroes around. In fact, it's pretty much impossible actually to hurt Superboy-Prime without getting him under a red sun.
3 Scarface and the Ventriloquist
Scarface and the Ventriloquist are an interesting duo. Ventriloquist has multiple personality disorder; he's a meek natured man who does the bidding of his dummy, Scarface, a violent 1930s style gangster. Together, the two commit all crimes, challenging even Batman with the ferocity of their crimes.
While the Scarface dummy has been destroyed many times, the Ventriloquist himself has never died; if he were to die, the whole thing would be over. However, people always have mercy on him once Scarface is out of the way, showing him mercy.
2 Mr. Terrific
Mr. Terrific is one of the most intelligent people in the DC Universe. He's also a multi-millionaire and a gold medal Olympic decathlete. He's been a member of the Justice Society of America and led his own team called the Terrifics. One of the most skilled heroes around, Mr. Terrific, has faced all manner of foes, but one he's never faced is death.
Mr. Terrific's back has been up against the wall numerous times over the years. Still, he's always managed to power his way through, using his prodigious intelligence and skills to overcome the odds and keep surviving.
1 Batman
Batman has faced many powerful foes both on his own and along with the Justice League. He's always been able to survive these battles and has been known to fake his death on more than one occasion. During Final Crisis, everyone thought that Darkseid had killed him but what really happened is that he got shunted back in time, moving forward from era to era and accruing Omega radiation in Darkseid's last-ditch effort to destroy the universe.
His fellow heroes might have thought him dead, but Batman was very much alive, trying to get back to the present, not knowing that he was Darkseid's ultimate revenge weapon. Thanks to Tim Drake, though, the day was saved.