I thought this thread died, like, weeks ago! Well, I'm happy it didn't, and as it's still here, I guess I can put up a few more.
Don't Fear The Reaper by Blue Oyster Cult set to Final Fantasy VII: Advent Children [http://www.youtube.com/watch?v=shEbyzbSyXg]
And yes, I happened to think it was an OK movie. While the story left a lot to be desired, and some of the charachters were portrayed in ways I wouldn't have done, the whole movie was visually stunning, which was more or less tha point.
Foo Fighters' The Pretender set to Deathnote [http://www.youtube.com/watch?v=ODA0Rr6OqGk]
Thought this one was pretty good, too. Plus it's Deathnote. You can't go wrong with Deathnote (unless you use something like 'Detachable Penis').
There are some others I can't find that a friend showed to me; If I ever do find them, I'll put them up here.
Apologies Abound.