its golden, and this is the prove
Put the banners in the middle of the text + in the end, you will see a CTR at about 5%-20% depending on the site and content.
Makesure the backgound and the text matched the text on your webpage, that way the surfer actually have to read the banner before they know its add. and dont se it as a add - its actually more of a content related link, surefers love it