I am getting a new PC and I want to get Professional because my CPU allows Virtualization. Now the PC is Vista 64bit Basic and if I purchase the Windows 7 64bit Professional will it allow me to upgrade?
Yes with a clean install. To be honest I wouldn't bother with Pro unless you really really really need an application that will not run under 7. The only real advantage is XP mode, however performance in a virtualized environment is less than ideal.