This is a bit of a novel, but if you're really buying one it might help..
As far as I know, the toshiba gigabeat is the best player.
This is coming from someone who owns an ipod (80 gig). I have no problem with the ipod as far as playing music goes. To me Itunes is the problem. if you have a pretty good directory structure with your mp3s, you might want to consider the fact that that means nothing to itunes. Itunes imports your music to the ipod. It exclusively uses the ID3s (all the information on the band, title etc) that come inside each mp3.
Problem being that if you've been downloading from here, there and everywhere your ID3s are going to vary. Shit is going to get messed up. Some people might put "the prodigy" as "prodigy" in the artist. That means there is going to be two prodigy selections. Say an ID3 is missing from a song in an album? the track will find itself in some silly directory in the middle of nowhere. Things get messy unless you've been incredibly pedantic from day one. I think most people would have their collection fairly well sorted into directories so dealing with this ID3 bullshit is a new step in lameness.
For me, I got really stuffed over. I got tired of stupidly filled out ID3's and ritualistically removed them from mp3s when I got them. Itunes really didn't know what to do.
In the end I waited for support and installed third party player software (
http://www.rockbox.org) so that I could just play files through the directory structure rather than the obfuscated database that Itunes builds with ID3 information. I love the ipod now, but it was a lot of trouble that you should avoid if you can.