Wowhead has given us a few new features for holiday presents. The navigation tabs have been tweaked to showcase some of the features and pages they've been adding recently. There's also a super-cute wallpaper by Noxychu, featuring cartoon avatars of various Wowhead employees.
More interesting, however, is the Completion Tracker, which works with their profiler and client to track your characters' endless quest to 100%. Areas tracked include quests, mounts, pets, and recipes. It's still in beta, but it seems to be working fairly well. It also lets you exclude categories that you may not be working on.
The other feature that Wowhead added is one that I'm honestly not a fan of - the little "share" button at the bottom of blog posts. I know we have it on Wow.com as well, but I still think it would be better not to have it; people are perfectly competent to submit links to Digg or Facebook or whatever without you encouraging them to do it. That's just a personal opinion, though.