OK, I use the term "upgrade" a bit loosely here. There is no upgrade path from 32-bit to 64-bit versions of any edition of Windows, period. However, you can preserve your Active Directory domain, DNS settings, websites, files, whatever, through a slightly long-winded process and get from 32-bit to 64-bit without: Having to uninstall Active Directory from your network and then piece-meal it back together workstation by workstation; Having to do system state backup/restores which won't restore all ......
I've almost finished my first Umbraco project, which is probably the most awesome CMS I've ever seen. In case you've been under a rock (which, after having rooted around this thing, I am starting to feel like), Umbraco is a brilliant, ingenious, pure-XML-powered .NET CMS - sorry to say, but much better than DotNetNuke, and fully validates with XHTML 1.1 due to it's XML nature. It supports nested master pages, Intellisense with Visual Studio, custom user controls, XSLT rendering, Web Services and ......