Longhorn is officially "Windows Vista"
It looks like the next version of the Windows client operating system will be called Windows Vista. I think it is safe to assume that this name will only apply to the desktop OS - in other words, the upgrade from Windows XP. I expect the next server product to be Windows Server 2007 or something similarly not consumer-oriented, which is fine by me. Although saying it will take some getting used to, Windows Vista is not a bad name. It's not as baffling as XP, "vista" is a very positive and well-known word (but not overused), it is a bit more approachable than the big cat pattern from Apple (Tiger, Jaguar, etc.), and the metaphor is appropriate for a client OS that is promising a lot of media/visual/eye-candy features. Here's a URL with some details and the announcement video:
http://www.microsoft.com/presspass/press/2005/jul05/07-22LHMA.mspx
Oh, and don't forget to note that beta 1 is scheduled for August 3, which is pretty soon!