I'd have to agree with CP. I used to have a 30GB Gen 4 Ipod never managed to fill it.
I now have an 8GB touch which is still only half way full. I us it more as a PDA and mobile game console than anything else.
If you want to limit to something that only plays music an Ipod Nano should be more than enough. you could try an Ipod shuffle if you don't need a screen.
There's many brands out there to test, Creatve, Microsoft, Sandisk etc...
Most are cheaper than comparable Ipods, but may be less intuitive.
Start reading reviews, you'll find you get lots of information from them.
You can start with something like this:
http://www.pcworld.com/article/125906/t ... based.htmlAlso like you I always look for MP3 players I can strap comfortably to my spleen.

you never now when it may come in handy to have such a feature.