Have ya'll seen any studies on what if any colors make people click more? Like a site based on blue or red or green?

I have not seen any reports or information on this. What is important is that your ads blend in with the general theme of your site. This goes for color scheme as well as font type and size. The more that your ads look like your content, the more clicks you will get. People as a general rule don't like ads.

You know what... I've been with AS since July 2003 (yes, the beginning) and I really don't think there is any correlation (at a generic level) between selecting colors MATCHING site design or not and CTR.. it's really a mystery. I tend to have Adsense color schemes that CLOSELY mimic the site interface... but not necessarily blend in 110%....

A bit of contrast is essential to draw focus to the ads - no?

Rob