None, use a mac. I have virtual pc installed but rarely use it. Within vpc are all versions of windows installed. I keep the windows versions backed up as zip files and run no antivirus on them either. If they burp, I simply unzip and overwrite the image. The favorite of all the windows versions is xp home. I can also boot to any of them making this mac a 100 percent pc. Only reason for that is a large windows only game. Most games run fine in vpc. Vpc runs windows in a window or full screen. It can run multiple os's at the same time. This way windows doesnt slow down because the registry never grows. It's always a fresh install.

I mostly use the mac, a child could use a mac, you nearly need a degree to use windows.

Keep it simple.