I just found 9 CDs (6.3 GB) worth of MP3 songs I had burned back in 2002. I am adding them to my portable hard drive now, which means I will also add them to my iPod once I connect it. I'm really happy about that. I am planning to establish a huge "Music Drive" which I can access from anywhere in the world since I will create the virtual drive behind my firewall at home.
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.