As per usual, Blizzard always says that their games come out: "when [they're] done." 
 
Unfortunately, Bobby Kotick himself has said that it will be out this year, with Mike Morhaime of Blizzard feebly saying: "We're on track." 

(Source: 

http://www.eurogamer.net/articles/2010-08-05-confirmed-cataclysm-out-this-year) 
 
Irvine is about a three hour drive from my apartment in Isla Vista, so I heard a collective "Ay Carumba" around the same time Kotick made that announcment.

I expected it this year anyway, it would be about on track with how long BC was out before WotLK came out.

Blizzcon was pushed back two months for one reason, the subsequent launch of Cataclysm.

So is the argument that Kotick is trying to push the game before it's finished? Because I thought they already mentioned it was coming out in October.