Have been a LONG LONG user of Linux as a server (hosting VM's XP / Windows 7 mix) and file / print sharing.
I used to avoid MS like the plague as far as SERVER environments are concerned - probably because my first experince was Windows NT (Windows NeanderThal or Windows No Thanks) which was SO HORRIBLE that it put me off Windows servers for ages.
(Note I'm using a server in a HOME environment where we have around 8 machines (most of which are actually mine for testing -- not a corporate environment which has other considerations).
The problem now with the latest Linux distros that they are trying to be "A Better Windows than Windows". You can of course customize them but I haven't got the time or patience to do this any more. To select what packages to install / leave out now is a 100% pain and if you do it wrong the chances are the system will give errors.
I've looked at the new SUSE 11.2 -- slick and polished - bit I don't NEED "an alternative Windows".
I've just been looking at Windows Server 2008 R2 (got it from Technet) and I'm REALLY IMPRESSED with it so far. I've installed the STANDARD version - you don't need datacenter or Enterprise version for a home server.
It runs vmware server on it just fine (although I might go the whole hog and use the Hyper-V virtualisation -- need to do a bit more research).
I'm quite happy letting MS do the updates than having to mess around with Kernel compiles etc.
Incidentally as a HOME server there are some considerations that you might want to do to make it more like a Desktop OS than a pure server for example add multi-media to it.
This guy does a great job at this . Convert your Windows Server 2008 R2 to a Workstation! - Multiboot Installation
Windows 7 VM's run just fine on W2008 server (they should as there is a lot of common code).