Well I did a little bit of testing, and I found that obviously 128kbps wasn't necessary with headphones or through the little speaker, but the best size to quality ratio that is acceptible that I have found has been 48kbps through WMA. Of course my collection isn't at that rate, but I did find a good program to do it... Power MP3 WMA Converter. It makes it quite easy... I just got around to re-encoding about a gig of music (the after-encoding size) and it was pretty painless.
If anyone is interested in getting it, feel free to contact me on AIM btw. Username Louse76.
