Adsense should really be a last ditch effort. You need to try to get in all the CPM networks before you settle for Adsense. I work with Tribal Fusion and Viralytics Media right now. They generate a much better eCPm for me than Adsense ever did. Tribal is great for in page display and Viralytics handles some in page and all my pop-unders. I also have used ValueClick and CPX network in the past and have had similar success with them. Don't sell yourself or your site short. Try to get in with the big guys first.