I’m always encouraging people to try Wordpress. It’s easy to use, simple to set up, and there are some great themes that work right out of the box, with minimal tweaks.
When selecting a theme, it’s important not only to think about style, but to think about how the content is organized. How much content will you have, and what kind? How will information be organized? How will visitors find what they are looking for?
I find it’s useful to install several themes, and test them all out. Then you can find the one that has the best layout and structure for your content, and you can customize the look and feel to suit your own organization’s identity.
Here’s some fairly recent best-of lists to help you find your perfect Wordpress theme. If you want someone to help you set it up, drop me a line. It’s what I do. 
10 Best Free Wordpress Themes of February 2010
Top 10 Free Wordpress Themes for 2010
2009 Year-End Free High-Quality Wordpress Themes
Fresh Collection of 25 Best Free Wordpress Premium Like Themes 2010