Deja Vu (2006) - 7/10 (one of the best time travel themed movies in general as there are not many I score a 7 or above)
p.s. I used to be a big fan of Spy Game(6/10)/Man of Fire(5/10) though.
side note: I am surprised that Unstoppable is got the most votes currently as that movie is pretty average. I would expect Deja Vu or Man on Fire to be the most popular of those among the masses in general.