The worst people on CL are people like me who actually know the value of what they're selling and want fair market value. The best people are the ones who just want to clear out their garage and price their stuff accordingly. Sometimes the flakes are the best because they're more likely to fall into the latter category. My last CL purchase was from a guy who I had to email twice before he finally responded half a day after the second email. Turned out to be a really nice guy and I got a set of Mavic Elites at a killer price and enough extra goodies thrown in to almost justify the purchase price on their own. The front wheel I'm currently using was another CL purchase from someone in the latter category, racer type who knew what he was selling but just wanted to clean house and sold a 2 year old silver Mavic Elite for $50.

ebay is much harder to get bargains on because even if the seller doesn't know what he's selling "Shinamo Ultra 6600 Breaks" :-) the buyers will figure it out for him. Shimano road shoes are a good example, I've seen R075s listed as everything from RD75 to RO75 and more.