This is my site http://making-money-online-auctions.co.uk, havent made it live as not sure if im allowed. Ive only Put the one ad on my site with a couple of search boxes add one ad unit at the top. I read somwhere that you make more profit from one ad as it is more related to your site meaning more clicks and also google will show the higher paid ads first and go down as you add more ads.