I currently own a website with around 350-400,000 visits per month (although I expect it to climb shortly) currently this along with another site (slightly smaller) are running from a dedicated server which is being funded out of my own pocket.
I am looking at perhaps running some banner ads on that 1 site (although not the other) to try and cover some of the costs of the server (or if I'm lucky perhaps the entire cost? naa, didn't think so...) but I'm not sure which advertising company would give me the best payouts.
There is one requirement however that I can not use contextual ads, the nature of the site is such that it would get a lot of advertisers of scam websites etc, this website is there for the community so I would rather not have that sort of ad on it.
I'd suggest you do a search on your favourite search engine. There are a number of advertising agencies, some offer CPM banner adverts, such as Valueclick and Casale Media, others offer different programs.
It depends on subject of your site. If it deals with autos -then best choise - affiliate program that deals with autos, if your site will visit users who interestrd in different security soft - than try to use Software-related affiliate programs.
Any way it worth to try some differrent programs, and investigate how it converts. Good luck.