How about making a nice list of well paying advertisers you had/have deal with and you know they pay well. I will start the list 1. Google adsense 2. Yahoo ypn 3. Casale media 4. Fastclick 5? 6? 7?
Adbrite can pay more than Google even but you have to build up a network that buy ads directly. Their network ads don't do so hot sometimes and even have adware installers buying clicks.