We found out a few choice tidbits about Cataclysm, including what's going on with the Blasted Lands revamp, the possibility of more old-world heroics like Shadowfang Keep and Deadmines, and the state of the Plaguelands after Arthas' defeat. How Tol Barad will (and won't) be like Wintergrasp also came up.
We also learned a bit about Wrath's design philosophy, including what Blizzard liked about Wrath (questing), what they didn't like (limited attempts on bosses), and what's sticking around for Cataclysm (Dungeon Finder).
And that stuff's only the tip of the iceberg. What was in the Q&A that spoke to you personally? What are you excited about now that some of these questions have been answered?