<10 Gb
Most of which I grabbed when Napster was less than legal. A lot of the songs are absolutely shit quality, like 128kb/s or less but I keep them because they're obscure and services like Google Music, iTunes, etc, don't have them.
For the most part, I use streaming services like Pandora, though I just recently cancelled my paid account with them and have been revolving between Slacker, Spotify, etc, to figure out which streaming service is best. I liked Pandora a lot, but they recently revamped their website, and it was glitchy as fuck. Couldn't stand it.