I have read several Vista reviews online from technical people, and most of them seem to miss the point: Vista is an operating system - as such it is not about the pre-installed games or sample applciations, what matters is what is under the hood. Of course there is security and performance and all the things you expect from an OS, but I am talking about what Vista makes possible as an applciation platform. John Dvorak is on the right track in his thinking about this.
What I am talking about is Windows Presentation Foundation, Windows Communication Foundation and Windows Workflow Foundation - in other words, the .NET framework 3.0. Collectively, these technologies are enabling developers to write applications with incredibly rich user interfaces, integration with back-end server technologies and business processes in a very straighforward and easy way. In other words, Vista is going to raise the bar for what is possible, from a paractical perspective, for applications running on a PC.
Developers have been playing with these technologies for over a year now and we are starting to see a few examples of applications that leverage the new platform. Lester's WPF blog has a video of one of these applications - check it out.
If you are a developer make sure to visit the Vista developer center on MSDN.