I started cycling about 8 months ago using an early 90's Giant MTB that I did some work on to make more comfortable and roadworthy. As I get in better shape and do longer rides, I'm considering an upgrade to an endurance road bike; something like a Giant Defy or similar.

I've been shopping on craigslist but don't have a good idea of value. I've discovered the bicyclebluebook.com website but most bikes I see are priced above the highest values and some well above.

Is bicyclebluebook not all that accurate or am I seeing adds from people that don't have a realistic idea as to what their bike is worth?

I'm not looking to get the deal of a lifetime but would like to pay a fair price.