I personally use an Ipod classic 80gb(though i HATE Itunes) but if I'd have to reccomend, I Say sandisk sansa has the best value. I've borrowed one from my friend before, I think his was 2gb + he added a 1gb card. it's cheap! with good UI, and good sound quality (though I'm not an expert on sound, hehe).
I also love using my PDA, especially for video (big screen, beats the ipod anyday) but the problem is battery life =( I hate having to charge my phone everyday (without video usage I can get 2 day's worth of battery)