I've been looking for one of these for some time now. There are a few others that are quite a bit more expensive, and there's also the waterproof cases available at waterproofcases.net for regular mp3 players, but this looks like it will be perfect. 128MB isn't huge, but enough for a 2 hour session if you compress your mp3's at 96 or 128 or so.
For $50 bucks, it hard to go wrong. I'm ordering one now.

Actually, it's even less, apply coupn code "DEALNEWS" for 10% off.