I've pointed this out previously to people curious about WoW's in-game demographics, but Armory Data Mining is really a fantastic but underappreciated site. To be specific, there are actually two sites of interest here -- the actual Armory Data Mining and its related blog. Zardoz, the creator and maintainer of both, uses the former to collect and update statistics on class, race, and sex popularity in WoW (in addition to reports on class battleground performance and profession popularity), while the blog is often used to look at smaller issues or questions like the effort to distinguish between bear and cat specs through the Armory.
Zardoz posted his newest collection of statistics this past Wednesday, all of them updated to reflect the patch 3.3 game world. Perhaps most interesting is that paladins have knocked death knights out of the #1 spot, with retribution being the most popular spec (and, as a druid player, I think I'm seeing a bit of decline in balance popularity here as well). If you're at all interested in in-game demographics as of patch 3.3, I highly recommend a trip over to both sites.