Adsense will be the top preference by many, next yahoo search marketing, you can use some inline text advertisers service like kontera if your site is rich in text content
If I were you, I would not fool with adsense. A lot of people like adsense because of the minimal effort on the writers part, all they have to do is write articles and wait for someone to click on it. But, you could make more money if you set up CPA advertising such as Marketleverage in which you can be paid up to $50-$100 just for one sale/lead! My biggest advice to you would be to make sure to pick the right offers to promote, as many offers are scams and horrible products. I would also avoid Clickbank because they pay monthly and their rules are stricter. Good luck