Warcraft, God of War, Halo, Gears of War, and Prince of Persia all have (Or had in Halo's case) potential. I was going to include Onimusha in there, but Resident Evil and Silent Hill were pretty average (And the RE sequels flat out sucked) so I'm expecting Oni to be the same.
The one that I think will be good, though, will be Max Payne. That pretty much is a movie as is. Also, Kane and Lynch was supposed to be turned into a movie but after seeing its lukewarm reception, I'm not sure if that's still happening. Which sucks because I was really looking forward to seeing Bruce Willis as Kane and Billy Bob Thornton as Lynch.