I know a few things about mp3 players, anyways some models to look for..
yeah, IPods aren't just popular for nothing these are good quality, easy to use and ofcourse it has the sound quality, which is most important to me. You can either get the 20GB ones (I think they come with color screens now) or the 30GB photos. This is totally up to you, what you think you will need.
However, recently Sony released an IPod "killer", The 20GB NW-HD5, this baby kills the IPod because of its battery life of about 28 hours. It's still kinda new though, and you may not like Sony because they use different file formats and such, and this is still a new product so its still not that reliable.
If u want a real small and harddrive based mp3 player, the IPod Mini is the way to go. However I think the normal IPods are not that big already.
Flash based players still have their advantages, because theyre not that expensive, don't weigh as much, probably some other things I cant think of at the moment. Anyways the
Creative MuVo TX line or the newer Creative N200 or something are good, they're a little better than the Shuffles.