The Death of Superman didn't really ruin comics. Like Solid Champ said, at the time, it was marketed as this huge event, and everyone thought it was going to worth a lot of money in the future, but it was mass produced (which is why marvel now only sells a number of their event titles). While the comic book death is comical and frustrating at times, it just makes the good comics stand out even more. Comics as I'm using it here would only apply to anything published in the two big house's multiverse. Take for example, unstable molecules, the recently released batman earth one, all star superman, civil war, house of m, a number of green arrow stories, sinestro corps war, and a collection of jsa as well. Because comic book death is so common, and not something that really means much anymore, we've come to expect it. And it brings a greater appreciation to good solid story telling. When I think of Batman, I don't think of the whole canon and ex canons and various incarnations. I think of the various stories that stood out that were amazing experiences to read. Civil War and House of M both feaures characters dying, and returning from the dead in one way or another, best marvel events imo.
For me, anything in between the death and rebirth of a character is filler, and rarely has a gem. But there has been exceptions to this as well, take Batman and Robin. So it's not that comic book death killed comics, there's just bad story telling.