I don't know CSS, just a bit of HTML, so Atahualpa has been a life saver. This is the first time I used it, thanks to a positive review from Doncaprio.
I'm using the theme on my person blog -- www.joanko.net
I love the minimalist design of new themes like Twenty Twelve (default Wordpress theme). Atahualpa can do this too. It's fantastic how adaptable the theme is.