Yes, I know that I could have used KVM, VMWare or VirtualBox, but I wanted to use what's included already.
KVM is included, you just have to select it. There is a loyal following of Xen in the community, but I use KVM for my servers. I'm often called 'dumb' for even talking about KVM, but I like it. (and I'm not saying, nor have I ever said, that KVM is better than Xen)
But, using the interface is painfully slow. I opened up Firefox and browsed the web a bit. The mouse cursor lagged a bit and whenever I loaded a slow /large website, it seemed asif the whole VM lagged behind... .. BUT, I want(ed) to see if this is a reality for the average desktop user, or not really (yet?) seeing as most modern PC's have far more CPU & RAM resources than what is actually needed by most.
I assume you're using VNC to connect? It can be painfully slow with some vnc clients, and workable for basic stuff with others.
Using MS remote desktop to connect to a VM running Windows works pretty well, but not when you're trying to view anything with graphics. (like watching videos)
There's the SPICE protocol which supposedly handles these problems, although I haven't tried it yet.
It would be nice if you could run your OS in a VM, then use some tablet with a huge screen to connect to the VM and not be able to notice a difference in speed. I think that's a ways off in the future, however.