Used iPod worth it?

I am considering buying a used ipod off ebay (trying to save money). What I am trying to figure out is: Would a use ipod (original 20gb is what i was looking at) worth it? What I mean is will it still hold up or could I expect the hard drive to crash any day? I guess my question is what is the reliability of the original ipods like?
Thank you!

One problem with the originals are that they _will not_ work with a dock AFAIK. I would shoot for a 3G if you're going for used.

One thing you want to watch out on used iPod is the battery life. The rechargeable battery on iPod do not last forever.