I was talking with a friend of mine in I.T. at the company I work for, and he has a friend who works at Microsoft and is on the Windows Development Team or whatever title you'll give them.
Anywhom, I brought up Vista Ultimate and its "extras", and he told me that because of the ''unexpected" flood of Vista issues microsoft had to divert it's resources elsewhere and have SP1 cover more than internally-planned. Also, believe it or not, supposivly the Driver and Application Compatibility issues (Which technically was not Microsofts' fault and thus didn't need to do anything) made Microsoft very unhappy since it gave many software/hardware developers more than enough time to prepare, and basically forced Microsoft basically play hound-dog to all those companies.
He mentioned that come Late Q2 to Early Q3 of 2008, Microsoft will have a "wave" of Extras coming covering functionality, aesthetics, and even performance (seems a bit unfair if performanc extras will only be for Ultimate users though).
Take it the way you want it, which is probably with a grain of salt, but hey salt can be tasty.