Developing a free ad theme for wordpress, what features should I add?

I've noticed loads of micro niche sites look terrible and spammy.

I'm developing a new free wordpress theme that will have loads of customisable options to help make wordpress ad themes look a little less shite .

http://i47.tinypic.com/i2m7gx.jpg

Here's what I've got so far, I was wondering what features I should add to it? Where are the best advert placements for good Click through rate?

I'm planning on theming 20 different skins for this once it's finished, including a lot of niche specific ones that can be customised easily!

Well, micro-niche sites aren't bad looking because there aren't themes out there that look good imo, but I guess that's a whole different story.

Options for ads in every possible place might be useful. Maybe the option to rotate more than one network at a time, assuming that doesn't break TOS? The ability for someone who has no idea or need to program a website to easily customize the colors, logo, and entire look of the site is what people would want imo. A Drag and drop interface?