Most likely, although there are a couple that I couldn't remember off of the top of my head, Marvel-wise. Although I'm pretty sure Batman has never "died" and been revived through magic/aliens/assorted BS. I don't ever remember the Hulk kicking the bucket, either. But who knows, I'm sure there have been series where they've both died, and perhaps never come back. I know for a fact that Captain America and Ultimate Spider-Man are as dead as a doorknob at the moment, at least.