Definitley Chrono Trigger and Chrono Cross, Mitsuda is a true master of videogame music

Nobuo Uematsu is the best. He's made the music for all the Final Fantasy games. So I'd have to go with the FF series as one of them.
All the Shin Megami Tensei games have good techno-like beat songs to them and I like that.
Some of the Metal Gear Solid games have some pretty good soundtracks.

Umm...the best soundtrack...
1. Chrono Cross
2. Final Fantasy 8
3. Kingdom earts
4. Legaia duel saga
5. Ragnarok online

umm...thats it,hey izzat all from square?hueee? >_< ( except for the legaia and ragnarok... )

Final Fantasy, pretty much any Final Fantasy.
Chrono Cross and Chrono Trigger
Guild Wars

Thats all I can think of off the top of my head, but thats probably 1/10th the total list of what I like ^_^

1. Final Fantasy 8
2. Gitaroo man
3. Tekken 3

1- digital devil saga
2- suikoden i
3- suikoden tactics
4- threads of fate
5- magna carta tears of blood

1. FF7 Advent Children OST (not really game, uh but... this is my fave)
2. Suikoden 4 (i love melody of sea)
3. FF6
4. Sonic Heroes
5. Kingdom Hearts

Have you tried bluelaguna.net ? they got almost complete soundtrack of some good games.

For me, the best soundtrack is that of BURNOUT 3 Takedown! I really appreciate punk/rock music and well, that just suited this game perfectly... I must admit that Burnout revenge's soundtrack just rocks as well, but i've got a small preference for burnout 3's soundtrack... It's just like that i think... Yeah i also appreciate soundtracks from the final fantasy series, prince of persia series, total overdose(i love latin music), nfsu/mw and tekken 3... i think there's more but i just can't remember for now...

DDR ALL SOUND TRACKS=] [Dance Dance Revolution] i love the trance music, and some hip hop or techno,FFX and FFXII, Initial D and o2Jams

Heck yes DDR music rocks. And so does anything Motoi Sakuraba does. I swear, Baten Kaitos has some of the best music I've ever listened to. Final Fanatasy X had some good music, too.

EDIT: And We Love Katamari had awesome songs, as well.

A list of 10 in absolutely no order at all:

-Silent Hill 2 (Really haven't listened to 3 or 4 though, but I prefer this to #1)
-Castlevania: Symphony of the Night
-Katamari Damacy
-Shadow of the Colossus
-Final Fantasy VI
-Chrono Cross
-Guilty Gear XX (I slightly perfer this one to the original, but both are spectacular)
-Suikoden
-Super Mario World
-Legend of Zelda: A Link to the Past

I have bad taste in gaming music... o_o

in no particular order.

1. Golden Sun/The Lost Age
2. Fire Emblem (both GBA versions)
3. Tactics Ogre: The Knight of Lodis
4. The Legend of Zelda: Ocarina of Time
5. Medal of Honor: Frontline

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")

I love the soundtrack from silent hill 4 it's simply breathtaking... my favourite song is "Room of Angels"

Grand Theft Auto radio musics..
Final Fantasy X and X-2..
Need for Speed series (Underground, Underground 2, Most Wanted)..