Plain Fields theme by lessthanweb is very simple, clean, readable and search engine optimized (SEO) theme. Search engines simply love this set up.
There are free and premium versions of this theme, there are three main differences between free and Pro version. With Pro version you will receive unlimited support, priority updates and bug fixes and all other features that are disabled in the free version.
Theme homepage: http://www.lessthanweb.com/products/plain-fields