A friend of mine is an athlete who runs and mountain-bikes a lot. He has a Creative MuVo C100 Sport and loves it. Came with arm band and has 256 MB plus takes SD cards for expansion. It's also splash proof. I played with it for a little bit and it seems to be a great player for less than 100 bucks.
Do we have serious runners that might help with an MP3 (flash) player that works well?