Most MP3 / WMA players which do not have a user replaceable battery will meet this spec [with 2gb] (unless your operating system is Windows 98/2000), and even then you will get a disk/software (so that your PC can interface with the player).
Most MP3 players are nice & small - the down side is the display is tiny - I need a magnifying glass to see mine.
I also have an MP3/MP4 player, which obviously has a larger screen - if size is not critical, I would recommend an MP4 player, so that you can see the display, the price difference is not that great.
One other feature I would recommend for any MP3/MP4 player is a lock function on the controls - so that when it is in your pocket, you cannot accidently stop it playing.
Check out ebay - that is where I bought both of mine, the sellers could not be beaten on price - check that it comes with a mains charger, otherwise you will need to have it connected to your PC for hours.