There are quite a few WoW database sites out there. Thottbot was the first big one that I was aware of; other big sites include Allakhazam, the Goblin Workshop, and of course Wowhead. Then there are some lesser-known contenders (at least to me; it took me a bit to come up with them), like WoWd.org, WarCry (I use their news constantly, but never saw the database), GameAmp, WoW Guru, WoWDigger, and TenTonHammer (again, I know TTH for news, but didn't know they had a DB).
And now Curse, long one of the big names in Add-On and news sites, is throwing their hat into the ring with the very capitalized WOWDB, which appears to be in beta right now. It seems like a pretty complete database; it's got all the items, quests, NPCs, and so on that you would expect from a serious act like Curse. But hold on a minute, doesn't it looks a bit similar to a certain other WoW database site
Another update after the jump.