Presentation: HUGE! A Drupal site with 381 modules, 174GB MySQL database, and 200 million row tables
Here are the slides from my Drupal Camp Toronto 2012 session.
The site is ScienceScape.org, a repository of scientific research going back to the 19th century, down to the latest biotechnology and cancer release.
Update: You can watch a video of the presentation on Vimeo.