If you have a decent knowledge of HTML & CSS, I would recommend Montezuma. Unlike most themes, which only give you a limited set of options, Montezuma allows you to totally change the structure and appearance of the site through the use of virtual templates & CSS files. Sidebar on the left, on the right, two sidebars on the right, widget area in the footer, it's completely up to you. And you can design custom templates for those pages which require a different appearance. If I'm building a site based on the appearance of an existing site, this is the one I use, because it is so customizeable. The virtual template files are in PHP, but the amount of PHP code is very small and easy to understand (mostly function calls to retrieve information).
Here's a sampling of sites built using Montezuma, that show how customizeable the theme is:
Cartidea
Raise a Child
Warsztatgier
Bionic Style
Rishona Campbell
Beard Food
Mattress Warehouse
Venice Hongwanji Buddhist Temple