I wouldn't worry about the adsense ad position on your website. best converting themes are also the ones that reduce the number of times people will actually read your blog, and in the beginning stages, you shouldnt be posting adsense to your site. You should wait until you receive decent amount of traffic first. That can only happen if you made something that people like. Otherwise you will be trying to optimize your ads forever, and make that your only job.
The Color of the title should be same as your Post title. The desp (or text) should be black. & the link color shld b default (green). Thats what I'm experimenting with currently. It had worked well in a couple of days & I'm expecting much more success with that combo
I prefer blue title, black text, light gray URL, white background and white border, default font family and size, 336x280, 728x90 and 160x600 ads. I also tried the default green URL. I am not sure but I think green is better than black or gray URL's. I tried different font families and sizes. I think that verdana-default size or default/default size are the best combination. The default blue URL (#0000FF) was not good for me. Dark blue is better.