Flashkiller, eh? Only if Macromedia sits on their rear ends for the next two years, with thumbs firmly implanted in their anal cavity. Something tells me that won't happen though. Still, it will be extremely cool to have a compelling UI designer right in Visual Studio.
I've heard a lot of people talking about (since the whole XAML conversation came around) how UI designers should be the ones working on interfaces first, then programmers write the logic and wire up the UI later. The funny thing is, those guys are totally missing the point. The point in Microsoft bringing about the kind of disconnected-development paradigm from ASP.NET to the Smart Client, is to be able to, God forbid, PLAN your requirements, and have your UI guy go build the UI (in AfterEffects or “Sparkle” or whatever) and have the programmer develop the logic AT THE SAME TIME. Your development goes much faster, because you're not relient on one person or another to do your job.
Windows developers don't get that yet. That's because the VB.NET WinForms RAD environment has been the same for 10 years: Changing the designer only changes declarations inside the code... there is no duality between forms and logic. This new development model is just plain better and Microsoft really is trying to take the best of Windows development and the best of Web development and put them together. And it is a win for everyone. Even Macromedia.
So “Sparkle” may kill flash. Every product has a lifecycle. The key will be to see whether or not Adobe or Macromedia can adapt and evolve to this new environment. That is the true test of any business.