VM Fusion 1.1 wasn't really compatible with Mac OS X Snow Leopard. On twitter I read a post of @vmwarefusion that he (or she) tried VMware Fusion 2.05 on Snow Leopard which runs perfectly. One reason more not to use Parallels because it's listed on some blacklists of non-working software for Snow Leopard.
After updating VMware Fusion from 1.1 to 2.05 the virtual machine (VM) must be updated (don't know what exactly, something about 3D acceleration etc...) and the VMs are ready. It rocks!
VMware Fusion 2.05 is available for free on the VMware download page if you own a valid license and uses the existing license during upgrade.
