The End is Near, or at least on the horizon, for 32 bits

http://www.infoworld.com/article/05/11/15/HNms64bitplans_1.html

Apparently, the the release of Windows Server after Longhorn Server (aka Longhorn Server Release 2) will be 64bit only.  Current thinking has that in 2009 according to this article.

It has also been announced that Exchange 12, the next server, will be 64 bits only also.