I'm looking for a cross-platform widget toolkit that I can use for a C application that I'm developing. This application will only serve as a small front-end. I'm keen on good design and usability. Speed is less of a priority, but I'd still like something lightweight.
I realise similar questions have been asked, but I'd like an answer based on my requirements.
For C, I'd say the prime canditate is gtk. You'd want to use C++ for qt or wxwidgets, though the latter also has lua (yay!) bindings, which is the C way to get around Greenspun's tenth rule. Depending on your application domain less-hyped (but still mature) libraries like agar deserve some consideration. I'd mention fltk if it weren't for C++, too. Truly leet people would use xaw and have users install an X server under windows. On an again more serious note, eagle has to be mentioned just for coolness value, although being C++, too. Wikipedia gives yet more options.