A vote for the Sansa, it can be rockboxed, expanded with microSD cards and has the nano form factor. Rockbox it and it is drop and drag USB drive (no WM which is needed for the original firmware). I have been watching BSG and Simpsons on it inbetween teaching my english classes during the week's evenings (using WinFF to shrink the videos for the screen). They are cheap on ebay (for a slightly used one, $80 for the 8gb version), some people get them and then decide to go to nanos.