A Better Drupal API Documentation Site
The brainiacs over at Lullabot recently unveiled api.lullabot.com, their version of Drupal.org's API documentation site. While on the outset, it seems similar, there are some nice features of the Lullabot site that make it very worthwhile to use.
First and foremost, in addition to documentation for Drupal core, they also added the documentation for a large number of popular Drupal modules, including Views, CCK, and Ubercart.