There is a nice post over at Dosh Dosh highlighting some of advantages of using an Adsense optimized theme. The post also has a list of 16 of these optimized themes.
I have thought about using one of these themes for RevenueQuest. My only hesitation is that many of these themes are all over the internet now. Using a common theme makes your blog look unoriginal.
If you decide to go with one of these themes, try to edit it a little bit. You may want to change the graphic in the header or changing the color theme.