If you want an outstanding WordPress theme, you would be hard pressed to improve upon Atahualpa. This theme from BytesForAll.com is the most flexible I have worked with from a sample of about 30.
What I appreciate most about it is the relative ease with which you can customize the design. Atahualpa sports a very cool options panel accessible from with the WordPress administration page (see: Access Atahulpa Theme Options).
Almost any feature (if not all features) of the theme can be modified within these options panels. Though not exactly WYSWIG, it is far superior to modifying theme layout and design in the style sheet or making changes to PHP pages. So far widgets work just fine in either side panel.
I am impressed enough that I plan to make this the default theme for my blogging/web site clients. I’ll continue to report my experiences with it. I am interested to know how easily a person who is not a web-geek can pick up a few simple CSS concepts to make mroe advanced changes to the site design.