As you're no doubt aware, while the the .NET Framework 3.0 is installed by default on Windows Vista it can also be installed on Windows XP SP2 or Windows Server 2003. Which is great news for broadening the reach of your app, but what about features that can only be achieved on Windows Vista? My colleague Daniel Moth has been running some great sessions on this very topic recently, including at TechEd Europe, and he's pulled together a blog posting that covers all of the material he presented.
It's worth taking a look - these features can really make your application shine on Windows Vista and differentiates it from something that's just been ported over from XP. In other words, it's a way of making your app a true Windows Vista app rather than something that just runs on Vitsta.