One of my favorite WordPress Themes is the Church Theme from Studio Press.
I like this theme for a couple of reasons. One the layout is nice and clean. It provides an easy way to add some great pictures to bring the home page alive and capture the attention of the visitor. The biggest reason I like this theme is because of the way they have set up their link menus for both post categories and pages. This allows for more diversity in the layout plan of your site.
I have used many other themes and in fact you will notice that this blog is built on the Thesis theme which I really like for blogs but when you are building an affiliate site or a CMS site the Church theme rocks.
Take a look at some of the other themes Studio Press has developed, they are all top notch.