i'd say, prince of persia and uncharted. both take a lil while but , still easy. AAh, almost forgot Alone in the dark, is easy too, there is a guide for achieving the platinum on the first playthrough. Lol, that's the easiest one i think...
Resistance 2 is pretty easy aslong as you beat Superhuman the rest you'll get in a matter of time last one is the 10,000 kills online so that will take you a good amount of weeks.
Fallout 3 is moderately easy aswell, since the game has no online most of them are for finishing missions.
Alone in the dark & Bioshock. Both can be done in one play through.
Bioshock on Survivor with Vita Chambers turned off is theoretically possible to do on your first playthrough.
I certainly wouldn't classify that task in the 'easy' category, however. I know that people have done it, but definately not 'easy'.