You need to find the right balance. Whatís going to make you the most money without putting all your eggs in one basket? After creating two very small sites and seeing them start to become profitable almost at once thanks to AdSense Iím just about convinced that affiliates/banners at least in some cases are not the way to go. BUT and this is a big but I donít like betting everything on AdSense.
Where I do believe banners work is when you are working with direct advertisers. My largest site has one banner running at the bottom of all pages. This seems to work for me and the advertiser.