I have tried almost all of them Andy, and your right to get away from WordPress if you want to customize much. WP is great for someone who just wants to install it, setup sidebars, and write.
The two I like best for customizing, which I often do to write my own blog skins, are:
Movable Type:
http://www.movabletype.org/
Expression Engine:
http://expressionengine.com/
Movable type is easier to change layout on. They have what they call a "sytle catcher" which loads default CSS styles in fluid, fixed, 2 column, 3 column, etc etc. Changing styles is as simple as loading a custom CSS into the style catcher with colors and images to suit your skin. The default blog.css has not images and a few default colors. OTOH the php and html is fairly rigid, unless you want to delve into Movable Type's template system.
Expression Engine is easier if you want to really get into php/html editing. The CSS also easy to edit, although you need to paste it into their editor. Both use a modular approach to blog design: sort of like forum skin templates. But that seems to be the standard now days.
Anyway give them both a skin before you decide (both are free).