Yes, Vista will do just fine. You know I come across people who say ME was the best OS ever made. I mean think about it... WINDOWS! Of course it'll do fine. Basically every computer in the world is compatable with it now, and nearly all of them will come with it preloaded once it comes out. I seriously doubt your average user will change the OS on their new Dell to something like Linux or back to XP
They will just stick with whatever it came with.