In what is largely a response to VMWare giving away GSX server, Microsoft announced today that it will make Virtual Server 2005 R2 a free download.
I've been using Virtual Server for awhile now to host my personal server and it works quite well. I'm very excited for the built-in virtualization in Vista Server, but I hope they do more than just make Virtual Server part of the OS (especially in the creation of new images).
The other important news out of this announcement, as you might expect since it was made at LinuxWorld 2006, is that Microsoft will now officially support Linux in Virtual Server.