I've played so many games it's hard to remember. Though in recent memory, I think the sound track to the end parts of Mass Effect 2 was really good. Aside from that I can't think of anything really good in the last few years. Then again most of what I play have been first person shooters and while some of them had good music, none of it counts as "epic" or worth listening too outside of the game.
This not epic enough?
http://www.youtube.com/watch?v=ZiN6t7K7txw