I'd forgotten how nice old game music can be. Great crunchy synth sounds and surprisingly lyrical melodies. Check out Silent Light, from Chrono Trigger: ogg or original RSN.
This music is still available thanks to the preservation efforts of the emulator scene. Folks have ripped the music code from the cartridges and published it as files: rsn or spc for SNES, nsf for NES. So you get the original music, not a recording. You'll need a player / sequencer. I recommend NotSoFatso for NES and SNESAmp for SNES, both WinAmp plugins.
Archives of music are readily online. Zophar has a good store of NES music (beware: popups), and SNESMusic is great for SNES. There's a lot of music out there. Some useful guides are Skytopia's list and cly5m's list. I like Earthbound, Chrono Trigger, Super Metroid, and the original Zelda.