Suggestion for a GUI library?

I'm looking for a good looking GUI library, for free :D
What can you suggest.

Thank you for your comment.

The Windows API. Completely free. :D

wxWidgets.

I'm looking for something elegant to skin my application with;
Small tabs, pretty glass buttons, etc.

Windows API, use owner draw.

I would rather shoot myself than to owner draw so many controllers...
button, tabs, scrolls, checkboxes, radiobuttons, lists...