[lug] Favorite Distro for Hosting guest OS like Windows7?

[siegfried]

Are there any distros that are better suited for hosting guest OS's (like
windows 7) than other distros?

I have a 2005 machine and I want to install linux to host windows 7. I need
windows 7 to run Visual Studio 2010.

According a free windows program I got from www.cpuid.com I have an Intel
Pentium 4 640 Prescott 3.2 Ghz. Family F, Model 4 Stepping 3 Ext Family F
Ext. Model 4 Revision NO. Instructions: MMX, SSE (1,2,3), EM64T. 

I think this is slightly too old to have that special firmware enhancement
to better accommodate virtualization. What is the name of that feature?
Virtualization extensions? Does the absence of virtualization extensions
affect my choice of virtual box or VMWare or Fedora KVM?

I want to run virtualization to run windows and once a month make a backup
snapshot or maybe rollback to a pristine guest. (Development activity tends
to muck things up quickly with lots of versions of tomcat, apache httpd,
mysql etc...) This will be a development machine for IIS/Apache HTTPD,
Java/Eclipse and C# and oracle and mysql database and even MS SQL and visual
studio 2010. I want to install oracle on the linux and talk to it from the
Window7 guest.

Thanks,
Siegfried