Oooh, well, I'd probably go with Elrond, everyone he loved died eh (not exactly sure about his sons?). But Luthien and Arwen endured quite a deal of trauma as well. Especially Luthien, from the stories I've heard (I've never actually read the Silmarilion).
Now that I'm thinking on it though, Elrond really did have it rough, that whole affair with Frodo too, not being able to haven the ring and sending the hobbit on his way with it. I don't know if I'd be too comfortable with the gift of foresight either.
Yah, my vote's for Elrond, poor chap.
- P. Pondlily