(huh, I can already hear Dr. Polaris agreeing. Anyway...)
Superheroing is an inherently dangerous activity. Let's face it, the guys in the capes aren't just the police. A superhero is cop, fire fighter, and soldier in one, and what these professions have in common is that each is a person who saves lives by risking and sometimes losing his own. Add to that mortal enemies with world shaking power, and you're looking at people whose day to day living is very precarious.
But if you want me to believe that, at any moment, a superhero could die, then every now and then, one of them has to actually die. The stronger possibility of an unhappy ending is one of the major advantages of on-going, episodic fiction that comics should exploit better. Because when the bad guy puts the hero in his unescapable death trap and looks like he's going to get away, there's a chance he really IS going to get away, if only for someone else to capture him three or four issues later. That's the way to ramp up the DRAMA.*
Now, I don't mean to be morbid about it. I'm not in the "kill 'em, kill 'em all" camp. The deaths should be rare, if only so superheroes don't look like complete incompetants. And while they don't all need to be heroic sacrifices, like Barry Allen--they could be fatal mistakes, like Booster's recent demise, or victims of effective villains, like Vibe's or Blue Beetle's, or even the truly tragic cannon fodder, like Pantha--the deaths need to have an impact, on the plot and on the surviving characters. And because I like deaths to have impact, I'd prefer the dead remain dead, but I understand that any fantasy genre in which The Spectre is one of the oldest characters will have a looser definition of what death means.
And the deaths certainly shouldn't be advertised in advance. One, it's kind of creepy. Two, it robs tension from issues in which a death isn't advertised. I know everyone is going to make it out of an issue if it's not solicited "Someone makes the ultimate sacrifice." Three, it robs tension from issues in which a death IS advertised. Even if it's obvious Captain Lamb is going down with the ship, the death has a lot more impact if you thought there was a chance he could have made it.
And some characters, of course, can't be killed. The editorially protected icons, of course, are practically immortal. No reader would really want Batman (or even the Joker) dead, and more importantly, no one would ever believe he was really dead anyway, no matter how graphic the death. I would have said protagonists of on-going books were safe as well, but blowing up Oliver Queen to make way for Conner Hawke was one of the best moves Chuck Dixon made on his run of Green Arrow.
I though Peter Milligan and Mike Allred's X-Statics nee X-Force handled death brilliantly. Killing off 90% of the team (including the narrator) in the first issue served notice that neither the characters nor the readers could take the success of any mission for granted, and then played out the emotional effect of such a highly dangerous life would have, and then what the effect would be if some people, but only certain people, came back.
Now, I can already hear some objections, notably "comics are supposed to be escapist fantasy and I don't want to be reminded about things I find upsetting, like death." To which I say, "Stop reading superhero comics."
Batman watched a mugger shoot his parents. That's the basics. If you want to remove violent death from superheroes, you have to give up Batman. And Spider-Man. And Superman. And Captain America. Heck, get rid of World War II and all those nasty Nazis.
Superheroes is NOT an escapist genre, not if by "escapist" you mean "a genre in which you don't have to deal with anything in the real world you don't like." Superheroes is kind of the opposite of that, a genre in which VERY REAL PROBLEMS are exaggerated and distorted to be scarier, which somehow allows the reader to deal with these problems through metaphor and analogy. A superhero universe is a worse place to live, where everything we have to deal with exists, but with superpowers. (Cue President Lex joke)
The danger, the very real danger to their lives, the fact that just by signing up for the Justice League a hero puts a target on his back, the fact that they might die alone, or suddenly, and possibly in a painful, undignified way, and they DO IT ANYWAY...
well, to me, that's what makes them a hero.
*One of the reasons I didn't like Grant Morrison and Frank Quitely's Earth 2 was the idea that on "our" Earth, good can't lose. Well, that sucks all the tension out of the story.