I just changed the theme of this blog to PressRow, recently introduced at WordPress.com. This theme makes your blog look alot like official wordpress blogs and forums. Being pretty plain and simple, it does not distract the reader. The bigger typeface also makes it easier on the eyes.
My only gripe is the rather large header image. I replaced the original with a simple image I found in Vista. Still, with a paid upgrade, you should be able to modify the size of the image.
Update: This theme is becoming very popular now. I see that many of the favorite blogs that I read on WordPress.com have switched over to this.