Since May this year we've heard dribs and drabs about Microsoft's much hyped next generation Operating System. According to the internal calendar Longhorn is due to hit Beta 1 on February 16th 2005 and hit RTM May 22nd 2006. Don't be surprised if the Beta 1 date slips let alone the RTM date.
Currently builds aren't what you'd expect. Labs have been re-arranged to ensure that separate parts of the OS can be tested and compiled in different scenarios. Such a re-organisation prevents information leaks too. Microsoft are currently compiling 501x builds which have effectively started from the ground up, built on Windows Server 2003 SP1 code. As far as I understand the code was getting sloppy in main builds. Main no longer resides in build tags and Lab6 is just a memory. As the labs are componentised it's less likely that a winmain build will contain a feature set like WMP11 or any kind of new interface changes until they are ready.
Build 5014 is the latest compiled build internally at time of writing. Early in September Microsoft made the new changes. The new builds only contain the Luna theme, look and feel like Windows XP and they mark the beginning of .NET Framework 2.0.
For now don't expect a public debut of a new build on MSDN, the next public build is likely to be Beta 1 in February 2005.
Screenshot: Current Longhorn Builds