Zap2it.com has a largely ignored interview with Damon Lindelof and Carlton Cuse on their website. It's mostly about the announcement of three more seasons of 16 episodes each, but there is some new information about the type of characters who die in the finale:
So you're not going to tell me who dies.
Cuse: Well, at least five people die.
Lindelof: But, you know, not like five major, major characters. But a couple of major characters.
Cuse: I think probably if you're a close viewer of the show you could name all five people.