I recently got the go-ahead to make this drupal site publicly accessible:
http://knowledge.ilign.com
It's a software knowledge-base site. We built the site about 8 months ago, but it was private-access-only until a couple of weeks ago. This site hasn't got a large user-base - yet ;)
There's still lots of improving and tweaking going on with this site. Your comments about the site are very welcome.
These points might interest people who are thinking of creating a similar site with drupal:
--Theme design was easier than I thought--
The site has a custom theme, based on bluemarine. For a start I changed bluemarine's tables to floated divs, and then tweaked almost every style. I found the bluemarine stylesheet very user-friendly to work from.
There's a lot that can be changed with the stylesheet, but I soon found myself looking further - at the template files - to see what else I could change. I'm more a designer than a developer, but with some help I got into the php templates and made some simple changes to the site's html structure. As a newbie-developer, I was starting to feel pretty clever! I discovered php-snippets, and with more help I wrote some custom php to list new/fav/recent nodes on the site's front page. The good thing about php template is all the changes to the site are in one directory (mostly in one file), so I felt that the changes I made were lightly done, and easily undone.