Thesis is a WordPress theme with a ton of powerful options. It's main priority is the look of your blog. You can easily customize fonts and the result is a system where different typographical combinations has never been this easy on the Web. Thesis Showcase Gallery
The layout panel allows you to set up your blog to be 1, 2, or 4 columns as well as specify the width of the columns. Combining the font features, and the layout features means your blog won't look like everyone else's blog.
There are also built in SEO boosting tools like the title tag constructor. Color customization is coming along the way as well.
When you join the Thesis community before August 31, 2008, you not only get all the goodness that is Thesis, plus all that amazing support, you also get the innovative new Cosmo magazine-style theme at no extra charge.
The price? $87 for Personal Use (one site), or $164 for Developers (unlimited sites, whether yours or clients). Which is a whole lot less then Semiologic (granted this doesn't come with a bunch of pre uploaded plugins, but if you're on a budget and want power, flexibility, and SEO tools, this may be the theme for you.