Lunar I and II (though Sega CD is better than PSX version which is why WD tried to work in as much of the original music as they could)
Top Gear SNES (IMO some of the most impressive SNES music ever, as well as the absolute best SNES racer ever)
Final Fantasy IV (ditto to last statement, I like some other Final Fantasy stuff but IV was by far the best)
Persona 3 and 4 (Excellent highly original soundtracks)
Super Mario Brothers/World
Donkey Kong Country (all) and 64
King's Quest series (and generally sierra's old point and click stuff in general)
Maybe Cool Spot (wasn't a great stand alone soundtrack but really matched the game well)
Hmm, I'm having a hard time thinking of anything else I'd say I enjoyed the soundtrack of. Maybe I'll post more after I think on it some. At least you can see I thought outside the box