A friend of mine sold me a 200 gig external HD this weekend.  He sold it to me pretty cheap ($200) and told me that he left all his music on it for me and that if I wanted to store my stuff I would have to delete some of it beforehand as it was almost full.
Boy was he right.  It had 180 gig of tunes on it.  39,000 songs.
Some of it I can trash easily...some country music, some rap, some classical stuff I'll never listen to, but much of the stuff on it is like a gold-mine.
Practically every Beatles song ever recorded, same with AC/DC, Led Zep, and a whole lot more.  Quite possibly my best purchase ever!  I went from having vitually no mp3s to having a major collection instantly.