I know quite a few people have bought one of the many Nano-Style MP4 players that have been appearing all over Ebay for very reasonable prices. (Although I'm not recommending any particular supplier - an example can be found here)
Mainly manufactured in China these are pretty good devices and work well to synch music to in Media Center.
One major issue is the manual supplied with them. I mean do you understand 'Grow the play button'. The translation from the Chinese leaves a lot to be desired.
Fortunately I have come up with a solution and as a reader of this blog you can get it at a discount.
Garry's 1GB,2GB,4GB 'Nano-Clone' MP3/MP4 Player Manual