I would have to agree with wmoses. I use Musicmatch Jukebox to manage my digital music. I can record MP3 at 128, 96, or 64 kbps. (Remember that the higher the number, the better the quality, and the larger the file size. A song recorded at 64 kbps will be about half the file size of the same song recorded at 128 kbps, but the quality will be less.) I can record WMA at 64, 48, or 32 kbps. The same song recorded as MP3/64 kbps versus WMA/64 kbps will have nearly identical file size. However, the WMA will sound better, for technical reasons that are beyond me. If I was recording to play across my home system, I would want to record as MP3/128 kbps because I have a high quality home sound system that can translate that higher quality recording to a quality sound for my ears. However, I have learned that a high recording level is not needed for my Axim. Any handheld player and headphones system can only go so far to translate higher recording quality and an acceptable trade-off is a lower recording quality that saves file space.
Bottom line-record your music as WMA at either 64 kbps (my choice) or 48 kbps (wmoses' choice) and you can fit more music in the same space. But don't take my word for it- experiment