I'm actually a DJ of a college radio show that plays nothing but soundtracks. I have a collection of well over 200 hours of soundtrack music from video games. Trust me when I say I know my stuff. Here is my tops:

10. Final Fantasy X (while admitedly not my favorite, it's still a high ranker for originality)

9. Super Smash Bros. Melee (everyone loves remixes when they're well done. Melee was done perfectly)

8. Starfox 64 (a mix of the Starfox for SNES and all new music, each level is perfectly unique with a feel that sets you at the edge of your seat)

7. Tales of Symphonia (awesome variety to cover any circumstance, but the tracks tend on the short side)

6. Harvest Moon: A Wonderful Life (although most of the extra songs require Friends of Mineral Town to unlock, it's the perfect compilation of all the songs from the touching and addictive series)

5. Metroid Prime 2 (while lacking in variety, the songs set moods for the boss battles perfectly)

4. The Legend of Zelda: Ocarina of Time (definitive Zelda)

3. Final Fantasy VII (Any version or remixes - The top Final Fantasy game)

3. Metroid Prime (who can forget the freezing theme as you enter Phendrana Drifts or the volcanic march of Magmoor Caverns?)

2. The Legend of Zelda: Majora's Mask (beat out OoT because of a broader variety of music)

1. Star Ocean: Till the End of Time (Motoi Sakuraba made a huge statement with sounds that match every area of the game perfectly. Depth, variety and the credits song "The Little Bird")