Chronos (Incarnations of Immortality), Rachel (Marvel Comics), Chris (Charmed)... and Hiro (Heroes). I have always been fascinated with time travels and the characters who can do it. I think, this is the coolest power ever to possess, well, next to telekinesis and flight.
If I can travel back in time, even for just six months prior, I can make things better. That was the stuff of my day dreams. Maybe, on the following nights, it might make up my deepest night dreams.