C Gui Development

Hello all, it's been a week or so so it must be time for annother question from me :D - Anyway, as I understand it from my earlier post entitled "C & QT Question", Qt/gtk etc can only be developed in C++ rather than C, if this is the case then i'm not too concerned and will just move to C++, after all, apparantly the code from a C app will compile as C++! :P. So, I was wondering if someone could reccomend me a gui development type thingy (sorry, cant think of the technical name). I'd love to hear your opinions...Thanks.

only Qt is C++.
GTK is C, check out the tutorial here:
http://www.gtk.org/tutorial/
It's C code.

Thanks, something to read when I get back home :D