For the last couple of years, all of the serious projects I have worked on have been either web based, or had a non graphical user interface (services, command line scripts etc...). I can throw together a WinForms app or do some simple WPF when needed, but I've never really delved into some of the lower level API's like MFC or QT.
I understand that this depends on the situation but in general is it still worth taking the time to learn desktop development well or are applications moving to the web and mobile devices at a pace which makes this knowledge less relevant? Also, do you expect developers you work with to have desktop gui expertise?