Vista Ultimate is the ONLY Vista OS that you can run on Virtual computers

"Performance..." poster has it wrong.

got it backwards. Ultimate is the only Vista OS that is licensed to run on Virtual computers.

From the Vista EULA:

VISTA HOME BASIC & HOME PREMIUM:

USE WITH VIRTUALIZATION TECHNOLOGIES. You may not use the software installed on the licensed device within a virtual (or otherwise emulated) hardware system.

VISTA ULTIMATE:

USE WITH VIRTUALIZATION TECHNOLOGIES. You may use the software installed on the licensed device within a virtual (or otherwise emulated) hardware system on the licensed device. If you do so, you may not play or access content or use applications protected by any Microsoft digital, information or enterprise rights management technology or other Microsoft rights management services or use BitLocker. We advise against playing or accessing content or using applications protected by other digital, information or enterprise rights management technology or other rights management services or using full volume disk drive encryption.