Let me preface this by saying I rarely replay games. I like them, enjoy them, finish them, and don't go back, with exceptions to only my all-time favorites:
Wing Commander 1 - Oh man, this one blew me away. It was so good. And one of few games where doing differently.... changes which systems you went to and the game ending! One of the early games where multiple play-throughs really paid off.
Wind Commander: Privateer - 2
Halo: CE (a couple times solo, and countless times in Co-Op. it was peerless, there's a reason it seems to be on half of these lists)
Mass Effect 1 and 2 - At least 3 for the first, on my second time for ME2.







