Banner ads - do these convert for anyone?

I've been putting banner ads on the sides of my web sites, but they don't seem to convert for shit, even with what I expect would be targeted traffic. Does anyone find banners worthwhile? Am I better off just throwing up some Adsense ads? Curious as to what everyone else is doing (or not doing) with banner ads.

-e-

Part of the problem is that ads on the sides of the page usually have low clickthru rates because people focus on the middle of the page. The type of ads you should use will depend on the layout and content of your site. But if the visitors aren't coming to your site for information on products they want to buy, then AdSense works better than affiliate banners because you can get paid without having the visitors spend money. It also usually works better than the other ad networks because of its targeting capabilities.

People associate banned ads with "bad" ads. Usually they're very annoying and aren't very targeted (in comparison to text ads). Text ads have better click rates 90% of the time in my experience