Great thread idea! Here goes:
Halo:CE - Replayed countless times, I really have no idea. Same goes for Halo 2/3.
Halo: Reach - About 15 times I suppose. Currently no plans of revisiting it.
Metroid Prime 2 - Played though it three times. Two during 2005 when I first got it and revisited it earlier this year (it's still awesome!).
Dead Space 2 - Probably beaten it 8 or 9 times. Mostly for the achievements but even after I got all of them I still played it 2 more times because of its epicness.
Luigi's Mansion - Aproximately 5 times. Last time was 2010 (noticed that when my sister decided to replay it).
Super Mario Sunshine - 2 times. Last one was late 2011. Another game that stands the test of time!
I could go on forever ;)







