Mac OS X only: If you're looking to run Windows on your Mac, you've got a few options. If you want to run Windows 7 on your Mac, complete with Aero, Flip 3D and 64-bit support, try the new VMware Fusion.
I've been aching to run Aero and other nice Windows 7 eye candy in my Windows 7 virtual machine for a while now, so upgrading to Fusion 3 has been a nice improvement to what was already a really nice 2.0 release
The catch, of course, is that VMware Fusion isn't cheap. You can try it for free, but if you decide you want to keep using it, it'll set you back $US80 new, $US40 if you're upgrading. It's up to you to determine whether that's worth it to get Windows 7 up and running on your Mac in all its full Aero glory.