Ooookay, let's have a look see.
I haven't had time to really think about it, so this isn't gonna be in any particular order.
10. Halo (my friend plays this when he does some role-playing, it'S very epic)
9. Splinter Cell (sets the mood quite well)
8. Megaman Legends 1 &2 (Both have great tunes that do the series proud)
7. Jak and Daxter (this includes the ending theme from Jak 3, it has a very, how shall I put it...rural feel to it, what with the percussions and all)
6. The Legend of Zelda, Ocarina of Time, WindWaker and Twilight Princess (I put all of these in one since its in the same series, the tracks here are just awesomely epic)
5. Kingdom Hearts 1 (I listen to this one all the time, lots of amazing songs)
4. Super Mario 64 (So many memorable and catchy tunes)
3. Dragon Quest VIII: Journey of the cursed king (I desperately want this soundtrack, every tune is a piece of classical and baroque goodness)
2. Ratchet and Clank: Going Commando and Up Your Arsenal (these may seem surprising, but alot of the songs stuck out for me, good backround music for the most part)
1. Shadow of the Colossus (words cannot describe how epic this soundtrack is, every song you listen to has your heart pulsating)