I'm an on and off again fan of classical music and I got turned on this week to Amazon's "99 most essential" series. It's a pretty good deal - for anywhere from $6 to $9, you get almost a hundred classical songs in a DRM-free format. Sometimes they're even on sale for $3.
http://www.amazon.com/s/qid=1252216067/ref=sr_shvl_1-all?ie=...