Last year I looked at using VMware to run windows Media Center on Mac OS X and while it worked pretty well media playback was a bit choppy, so when I saw that WMware had launched Fusion 4 for Mac OS X Lion I thought I would try it again. Fusion 4 is designed for Lion and can integrate your Windows programs into Launchpad and Mission Control. VMware also say that performance is improved with faster graphics so I thought I would give it a try.
In this video I used VMWare Fusion 4 to run the bootcamp install Windows 7 in a virtual environment and then tried streaming a recorded TV show from my main Media Center machine. I also tried running Windows in what VMWare called Unity Mode where Windows programs can run as native apps without the Windows desktop
Full screen or in a windows it works very well.