Night - I debated going to something less that 320Kbps, but couldn't come up with a good enough reason not to. After converting my entire CD collection (actually ended up being over 400 CDs) I'll still have over 1/3 of the 120GB hard drive left. It took me 15 years to accumulate all those CDs (I sell a lot after they end up not being keepers) so I don't think space is ever going to be an issue for me. As for losing the mobility of the music due to its size at 320Kbps, that was a bigger issue - I have a Nomad Jukebox. I found that MusicMatch can downsample from 320Kbps to 128Kbps, while transferring MP3s from my PC to my Nomad Jukebox. Problem solved.

As for hearing the difference between the various bitrates. At 128KBps I can hear the difference. Once things get over 192KBps, it gets hard to tell the difference. I guess I just like to know that I've captured/copied as close to the real thing as possible.