Do you know any source for nice looking software designs? (non Web).
There are some good examples on http://emberapp.com. Mostly for Mac though ...
In this case... a lot of programmers tend to talk only about the worst examples...cause UI really depends on personel taste.
Have a look at this question for the worst examples: Stackoverflow Question
From my point of view i prefer clear looks...nothing fancy etc...but it really depends on the software and topic...hope this helps
I would take a look at http://quince.infragistics.com/, while not complete applications, it does show you some best practices/design patterns for both Windows and Web applications.
I'd also take a look at some of the Windows Forms component companies, DevExpress, Telerik and Infragistics. You can learn a lot from the look and feel of their components.
There is always Apple Design Awards or something like the Mobile User Experience Awards for mobile applications.