I did a count of the all of the CDs in the house. As it stands today, I probably have 100 GB worth of songs. That will be about 20,000 songs assuming 5 MB per song. Of course, from that 20,000, let's assuming a duplicate rate (because I buy a lot of complication CDs as well) of 5%. That still means I'd have about 19,000 original songs to have access to whenever I wanted.
Yay me! :)