Comic books are another rich vein of 'heroes' coming back from the dead so often that it's a running gag with some of them. (Jean Grey being the classic example, but given that her codename is Phoenix, I don't consider her the worst offender.)
I do think it cheapens the notion of death, and sacrifice, when other characters in the story (such as Beast, the White Queen and Cyclops himself) are joking about the inevitable return of a deceased loved one. Ironically, this is a setting that doesn't have a set technique for resurrection. Cyclops comes back the dead one way, Jean another, Colossus still a third, his sister Ilyanna an entirely different way. I don't even remember how Superman came back to life, but it's hardly the first time he's died and come back (although they usually don't make a year long event out of it). The only commonality is that a new creative team wants to use a 'dead' character and invents a way to bring them back.
Zelazny's books often dealt with immortal protagonists, but the one that most dealt with resurrection would be Lord of Light, where the main characters transferred their spirits into new bodies at the drop of a hat, and at least one character develops a technique to exist outside of their body.