MegaGames.com is a news and download site for hard core gamers. The site has been around for over 10 years, and first made the transition to Drupal 6 from a hack and patch Perl system a couple of years ago.
With the migration to Drupal 7, we concentrated on improving performance and migrating away from our own custom solutions to community contributed modules. Rather than roll our own, we preferred to extend and patch existing modules.
We added new social features with theUser Relationships module, and messaging services with Private Messages, making MegaGames.com (we hope!) a social networking stop for people who want to share their passion for gaming.
Another big step was migrating to Nginx. We used Perusio's nginx for Drupal configuration with a few modifications. Between Nginx and Boost we are serving a few million unique visitors per month quite well.
We're very pleased with the performance. Nginx + Boost for anonymous users is amazingly fast, and in benchmarks we have seen response times of less than a second for anonymous users under very high loads. For registered users we are well within are target of less than two second page loads at peak traffic times.
Overall, the move to Drupal 7 has been an enormous success.
Drupal offered the best mix of out-of-the-box / contributed features vs. flexibility and the ability to extend against other systems like Ruby on Rails (max flexibility, few contributed features) and other CMS systems that have great community support but more difficult plugin systems.
The overall positive and helpful Drupal community also makes a huge contribution in the overall speed and ease of the development process.
Our goal is to create a social networking hub for hardcore games, serving news, downloads, and giving fans the ability to share images and info about their own gaming rigs and consoles with each other.