What have you seen available? I'm not sure what the used digital camera market is like. If you can give us a list of what you've seen available, we can give you some opinions.

Have you checked the digital camera reviews, here? http://www.photographyreview.com/cat...T_3065crx.aspx

Note that the main review category pages mostly show currently available cameras. If you're looking at out-of-production stuff, look for the link at the top of the page that says, "Only Older Products"