I truly believe that Windows 7 is only a marginal upgrade over Vista. So if you already have Vista Ultimate 64-bit, I'd say there's no reason at all to upgrade to 7. Especially not if, as CJS7070 suggested, Vista is working fine for you. Seriously, Vista, with all the current updates and patches, is as good an OS as 7 is. It just uses a bit more resources from your computer, but if it's fast enough, chances are you won't even notice it.