I'm looking for a blog or website that showcases nice UI designs. Specifically, one that has examples of Windows user interfaces. I have a few of these bookmarked (like Beautiful Pixels), but they are very Apple-centric, and I have a need to divine some inspiration for a Windows application.
This may be rather small in terms of the scope you are looking for, but I check out Little Big Details on a daily basis. The site showcases one great usability element a day.
I don't know if this website is what you're looking for but it might give you some inspiration and examples of different design for a lots of situations. The website is Quince and the address: http://quince.infragistics.com/
One of the longest standing interaction design pattern sites around is a very useful resource. It's not specific to Windows, but has a lot of platform agnostic principles.