if you're young and listen to recent music, then owning is not that expensive
if you're older than dirt like myself and want to listen to lots of music from the last 40 years or longer than renting is a lot cheaper. add to this the fact that there is so much music to listen to that there is no sense in buying even single songs you might listen to a few times and then go on to something else
Oh, CRY me a TORRENT!
(Also, Led Zep is only available on Spotify, Beatles and AC/DC only on iTunes, how do I choose? No definitely, the cheapest option was to backup all my CDs -- and that's a massive lot of them. Vinyls are a bit more annoying to back up but then again... see above)