The "cool Vista stylings" are done using WPF, for which you'll need Visual Studio 2008. 90-day trial downloads are here. The "Express Products" (free, stripped-down versions) are here.
As mentioned Visual Studio 2008 has WPF (Windows Presentation Foundation) based development tools in it. Have a look in your Project templates for WPF Application along with WPF Browser Application and WPF User Control Library. All of these pertain to Vista WPF.
FYI, the answers before this were in response to a very poorly worded question. The OP did not make it clear that they were after a web page. Thanks to Shog9 for picking up the slack there.
This is NOTHING to do with WPF or VS 2008. Its a WEB application!
Lots of control vendors have produced some great looking controls, check out the ASP.NET controls gallery there is some cool stuff there. Another well-known vendor is Telerik who have created some real nice ASP.NET AJAX controls.
Note, this is not to promote their tools, I personally have not used them, they are popular, and it's just to give you the heads up.
In short, the look is pretty much fancy imagery. Unless Silverlight is used, which uses a subset of WPF and requires the plugin to be installed on the users browser, and requires VS2008 to create.
In terms of the screen shot, most of that is nice imagery, the buttons are probably rendered like that because you are running Vista, however, they could also be replicated without Vista. The page you show is not a Silverlight page, so it is not a requirement.
Have a Google for "ASP.NET vista style controls" there's tons of people after the same stuff :)
It's not a matter of what software to use - use whatever you normally use to design websites. If you want to make a web page that looks like one you see online, you can very easily obtain: