I launched IE and played MineSweeper as a quick test of 3D. On each I loaded Windows 7 64bit RC1, assigned 2Gb Ram and 128Mb Video. I have three VM apps to try out Parallels, VMware and VirtualBox.
Please note, my tests were neither scientific nor exhaustive. Here are my initial, (very) brief findings. So I decided to see how Windows 7 fared in this scenario. I've run XP in a VM on a Mac quite happily for the last 3 years (first with Parallels and recently with VMware).