iWeb 2 (the iLife '08 version, that is) comes with an assortment of 26 different themes, but if you're tired of trying to mod the Comic Book theme for your new blog, you may want to look at ten new iWeb themes from Jumsoft.
There's a good assortment of styles in the Jumsoft collection. I personally find the Teddy theme to be a bit twee and Flowered World is too feminine for my taste, but YMMV. My personal faves from the new collection are the sparse and paper-like Simple Info, and the pastel and plastic Business. An installer app is included to make sure that your new themes end up in the proper place on your Mac.
Jumsoft sells each theme for $9.99 or you can buy the entire pack of ten themes at a 30% discount for $69.99. If you're an iWeb fan and want some additional design options, take a look at the new themes.