honestly i would find a 'Sandisk Sansa e200 series (v1)' player as they can install Rockbox (www.rockbox.org) to them and it allows them to do more stuff that you cant with stock firmware on them... like play some minor games etc.
i mainly like it cause it supports ALOT (basically all the major stuff people use) of different audio formats... i use it for .OGG support myself plus it has alot of configuration options if you need it etc.
and best thing is... you can typically find these for like 50bucks (or less) for a pretty good sized one to.
p.s. i personally have the 'Sandisk Sansa e250' (2GB memory built in with a expandable memory slot) myself.... and the great thing is, stock firmware on the player can only use upto 2GB cards.... with rockbox you can use upto 32GB memory cards (i.e. the MicroSDHD ones)... only catch though is even though Rockbox can use the larger capacity ones the stock firmware wont be able to use it.... and since you need the stock firmware on the player to transfer files to and from it you will most likely need a external MicroSDHC card reader to transfer the files you need to it before using it in rockbox..... if you dont have a way to transfer files to the external memory slot (i.e. MicroSDHC) you can always transfer songs you want into the internal memory then load up rockbox and then use that to transfer the songs from the internal memory to the external memory slot