That was an interesting article. I do wish to point out, though, that Boromir and Theoden got dead and stayed dead in LOTR and Gandalf isn't really mortal, anyway. Also, Frodo can be said to have died of his wounds in a way.
Oh, don't forget that Beowulf dies at the end of his story and that is a very old tale, indeed.
Also, speaking of dying and coming back, though he doesn't do it until after Ragnarok...
http://en.wikipedia.org/wiki/Balder