OK, this may seem like a simple question, but why is it illegal to download an MP3 file if I own the title on casette or 8-track? Theoretically, isn't the industry forcing me to pay again for something I already own? And it's not like a 128Kbs MP3 file is that much better in quality, or anything...

It seems to me that if you can demonstrate that you own the music you're downloading, then this should be legal. Has anyone who's been accused of piracy by the RIAA used this as a defense?