Well I have had an ipod mini, ipod nano (2nd generation), and two ipod classics (my first one got stolen from my car) but I have not had problems with anyone of them except for my ipod mini's battery dying (because the girl who sold it to me thru craigslist sold me an ipod with a battery that was almost dead - after that I never bought an used ipod).

I do not know about the sad face problem. I don't think it should stop working just because you did not buy from itunes. I use all my songs/videos from various sources and less than 5% are bought from itunes.

Does your ipod also display a folder icon? If so, this might help. I have not tried it because i have not faced the problem yet.

http://forums.ilounge.com/showthread.php?s=a7dbb9b0d06cae916d706906fde2ae4e&threadid=135673&highlight=replace+hard+drive

Good luck.