Below is a very short list of other companies who've chosen the framework recently.
All the links are to the Drupal sites.
1) FedEx : A very well known express delivery company
2) The United Nations : A site that supports and inspires
people from around the world to take action in support
of the Millennium Development Goals.
3) Nike : A well known sports site with a large database
4) Warner Brothers Records : A huge site with a very different
Theme for drupal.
5) Freshbrain: A safe enviroment for high school students [where they ] will be able to do activities and projects using our state of
the art platform, tools, training and with the support communities and
advisors!
Community Portal Sites :
1) Team Sugar : Womens social network and community
2) Lifetime TV : massive Drupal site with a movie database,
television schedule, videos,
photos, editor-produced articles,
user-produced stories, games, tag
clouds, topic-based search,
and beautiful theme.
3) Project Opus : Local music community.Music events and people
where you live; free music hosting and play list.
4) Adrenaline Hub : The action sports community site with
news aggregation and video upload.
5) Global food network : A superb community site related to
food...recipe's , videos, blogs, groups and much more.
6) Gallery : A community site with photo upload great forums.
7) Now Public : A busy news site with features like Write a Story,
Upload Your Photos, Video & Audio and
Highlight a Story You're Reading
8) Our Media : Video producers and podcasters use Ourmedia
to show off their works and create communities of interest.
A site with audio and video upload and features like
Create your own channels!
Learn how to create cooler media
Grab rights-cleared footage & music
Upload your work to multiple sites
You own your media - no lock-ins!
9) FastCompany : A site with all social networking features,highly
interactive
10) Popular Science : Another informational site of a variety
of subjects with great social networking features
11) Forbes : The forbes.com office pranks network site.
Even the most serious business person needs to have a little fun.
Forbes.com has introduced the Office Pranks Network with
features like Submit and share
your office prank and vote/comment on other office prank videos!
Ecommerce :
1) Blankstyle : An ecommerce site selling all types of clothes and
accessories. Online shopping accepts all types of credit cards.
2) Zazzle : An ecommerce site for creating and selling t-shirts
3) Muziek-en-lectuur : A Germany site with a huge database
selling music cds and albums.
Educational: 
1) Harvard Science : Science and Engineering at Harvard
Universtity Site with a superb theme and great features.
Magazines & News:
1) Amnesty International : A news site..media,library,
campaings etc
2) The New York Observer : Best In Magazine
3) Twit Netcast Network : deliver podcasts
4) The Onion : American news site,very popular, with lots of
features
http://usmagazine.com/
http://theworld.org/
http://www.brusselsjournal.com/
Video & Photography:
1) Flixya : A Video Sharing site with social networking
features
2) SonyBMG : Britney Spears Blackout Magazine: Videos,
events, photos,Lyrics etc.
3) Warner Bros Records : Audio,Video .. a whole world
of entertainment by warner bros.
http://www.monabrooks.com/
http://broadbandsports.com/
Services:
http://www.seoposition.com/
http://ilign.com/
http://www.kizmetinteractive.com/v2/
Government & Public use Sites:
For all types of sites in drupal with superb themes please contact