WxWidgets is the new thingy in vogue now I think, I don't know if anyone has heard about it. It brings real OOP to C++ coders. It requires a high learning curve though. I use wxHatch to code Interfaces and (drag And drop :-P) and then code the main stuff in wxwidgets and then compile it on the platform I want to run it on. It also makes C++ look multi platform.
www.wxwidgets.org , Did I mention that it is free for commercial use as well.