From a realistic standpoint. When do you expect Cataclysm?

[Maleick]

They will probably do six months of beta or so. I love blizzard becuase they want to make sure they get it right. However this takes a long time

My guess would be 2011.

[MiRai]

I love blizzard becuase they want to make sure they get it right.

I hope you're trolling.

Back on topic:
I don't have an estimate of dates. But I'm going to assume that this will be the longest beta we've seen yet. In addition to giving us new zones/instances/raids from 80-85 they're revamping [quest flow and/or layout] over 40 old world zones. Obviously some zones aren't getting hit as hard in the 'cataclysm' but it's a lot of content to revamp and make sure it's all working as intended.