I've been thinking about this for a while, and there's no best place I know of to ask for help.
It would be very usefull if I could add a second Keyboard, Mouse and Display to my computer and use it as a "second computer". I have the spare parts, only lacking a usb keyboard, but I guess I could test the second machine with a joystick?
What I want to do is have my computer (Win 7) on one display and a XP on the other, being able to game while using other things on the other display (music, messenger, internet), and also maybe even gaming on both displays, so I could play games like Diablo II, Borderlands with my cousin without having to get a router and his PC to my house.
Could also have family use the 2nd display while I keep doing my things on the primary.
I know pretty much nothing about VMs, used only once.
Can't do it with separate keyboard/mouse, you will need to use one to control both sessions. And your system running the main OS and a virtual one will bog down. Get a higher end CPU and double the ram if you want to run a virtual machine all the time.