Thank you I didnt know that Google had an ad server !!
A newish self-service site to check out is http://www.isocket.com. They charge a fixed fee (and don't take a percent of revenues).
Although I have to admit that for the moment the free limit of DFP is way above what we need everymonth. But I hope that it will change soon ;)
@bjonathan - confused... why would you want the DFP limit to change if the limit is already above what you'd need each month (thus being free to you)? Or do you mean you're hoping your traffic grows to the point you pay ;)