Disallow.
Virtualization of OS X Server is such a big dealTM exactly because you are allowed to do it per the EULA. That's why VMware Fusion and its competitors support it.
If the situation for standard OS X were to change or would have changed in the last few years, the VM software vendors would support it immediately (and charge a sweet upgrade price for it). Since they don't, it's safe to assume Apple doesn't want us to virtualize non-Server OS X.
Ergo it's a similar situation to OS X on non-Apple hardware. Which for us means: Vote to close, flag, and downvote.
edited to add after +8 score: apparently, Mac OS X 10.7, the upcoming major release, will allow use as virtual machine client. Wile we should allow questions about that, I don't think this should lead to us tolerating the same questions about earlier versions (which will happen, e.g. For people doing compatibility testing)