Longhorn desktop 2005, Longhorn Server 2006

"Longhorn Server Won't Ship Simultaneously with Longhorn Desktop. In the topsy-turvy world of the next Windows Server version ('Will it be Longhorn Server?' vs. 'Will it be Blackcomb Server?') comes news that the next version, which will indeed by Longhorn Server, will not ship alongside desktop versions of Longhorn.

This is similar to what happened with the Whistler project, which morphed into separate Windows XP and Windows Server 2003 development paths. Microsoft hopes with Longhorn, however, to get the desktop and server releases a bit closer to each other in order to make life easier on customers. According to current schedules, however, what I call Windows Longhorn (desktop) will ship in late 2005, while Longhorn Server won't hit until early 2006. Since Microsoft likes to keep its server releases about three years apart, that's good timing. But then Microsoft was never one to keep to a schedule."

Neowin.net - Longhorn desktop 2005, Longhorn Server 2006