I used another site before Adsense, but it was something really crappy like "PayPopUp" or something and it was really terrible. Simple text ads were like $0.001 per click.
Iirc with Adsense there are a whole load of different ads you can use. Text based, banners, the featured ads you get at the top of google searches. I think you can also specify what size the banners can be.
Sign up to adsense, its free and you can view all the different types of ads before you implement them.