The Spelunky soundtrack is amazing and FREE right now (pay what you want). All of the composers work available on band camp is pay-what-you-want right now:
He's done the music for Spelunky, Super Crate Box, Ridiculous Fishing, etc. The Spelunky OST is 62 tracks long. So much goodness! The Worm still gives me hives when I hear it, though. Ha ha! So much ring tone potential. And actually pretty great to just listen to too.
Download options include MP3, AAC, FLAC, etc.