For me: anything from Nobuo Uematsu of Final Fantasy fame. (except his death-metal pieces from 10. I'm not into that stuff, it scares the heck out of me.) Capcom also made many of my favorite game tracks. The Megaman X games (X1 most of all) and the Street Fighter games all have wonderful music.
Castlevania, Starfox, Zelda, Mario, Chrono Trigger... There's just too many for me list. But I will give honorable mention to Marvel Superheros Alaska stage on the SNES.