Adsense income is not heavily depends on the theme you are using. Proper placements of the ads will make your income high.
AdSense-ready themes aren't all that an important of a feature, IMO. You can easily add ads to your sidebar via widgets using any theme. I personally like the 3-column themes that have two columns on the right-hand side. I like how you can have your content on the left, then a row of skyscraper ads to the right, and then your navigation links on the far right. It forces readers to see the ads whenever they want to navigate to another page. They have to pass over the ads to click the nav buttons/links.
look at this: http://top-best-themes.com/category/wordpress/adsense-ready/ Thats my collection of adsense ready themes for wordpress.