i was looking for a similar thing, but i found that most alternatives are flash based, so smaller storage and higher cost. the only other options were archos type media players that were much bigger to have a 3.5" screen for watching videos, and an inflated price to boot
in the end i got a second hand, but brand new unused, ipod classic 120gb for £100 from a cash convertors type place. i already had an iphone so i had to get used to itunes and tag stuff, which is a pain
i use it in disc mode and added a bunch of portable apps such as winamp, as when i plug it into another pc i can run winamp and play the music from it on that computer, so ultimately it can do what most alternative players can do, but the downside is you have to use itunes to use it as an mp3 player. you can use alternatives like mediamonkey i suppose, but you can't just drag and drop files like on the archos