cjackson92 said:
Dead Space

and Resistance (but the movie would find a way to suck)
Dead Space I can see working but the plot and characters of Resistance 2 made it clear that the guys writing the script have no idea how to tell a story in the present tense. While Dead Space could allow for something original, or in the vein of Alien at least, it could be another DOOM.
I think Assassin's Creed could work with a rewrite, although I think the upcoming sequel would probably be easier for audiences to connect with than the Crusades. Remove the genetic memory element and make the main character something of a renaissance Robin Hood - who kills. Unfortunately it could well degenerate into a clone of Wanted in the wrong hands.
I'd like to see a Killzone movie although I really don't think it could be any good.
I would really love an anime movie or series of Okami.
Random bad ideas:
Burnout as a Fast and Furious clone
SSX: The Movie
Little Big Planet: You make the movie
Soul Calibur - in the style of the Mortal Kombat movies