we just launched our new website at www.aadl.org running drupal. We are moving from Frontier. Drupal is going to give us the flexibility to do everything we wanted to do with usertalk, but couldn't. As far as we know, we're the first pubilc library to go to Drupal.
A new site dedicated to online games, mainly puzzle and logic games...
Some matters with i18n (still not solved) but it was really easy to set it up. http://www.fantaplay.it/
I'm hooked on the Chameleon theme. It's so friendly and simple.
LiveDistro.org is a slim deployment of Drupal features, but makes good use of the aggregator, url_filter, vocabularies, php category block contribution (nice!), anonymous submissions and comments (nothing better!), and of course the page and story modules.