I\'m looking to be able to build GUI applications quickly and painlessly as possible. I\'m competent (though not expert, and have no formal training) in C++, but have never used
I also use wxWidgets and use it all the time for Windows-only applications (the only downside is that wxWidgets is notorious for large .exe filesizes, which may or may not be a problem for you). I found it very simple to use from the start, especially when combined with a GUI designer (personally I use wxDev-C++).
I've never used Qt, so I can't speak to its simplicity, but I doubt the difficulty is on a vastly different scale than that of wxWidgets. However, what I can say is that no matter what API you use (wxWidgets, Qt, WinAPI, etc) your code will be "locked into" that particular platform, so don't worry if you feel that learning Qt will lock you into the Qt platform (because the same thing will happen with any of those APIs).
If you're working solely on Windows however, you may want to do a few simple programs with WinAPI first. That way you have a basic understanding of the lowest level of Windows GUI programming before you move onto Qt/wxWidgets. That said, if you're really into cross-platform programming, then don't worry about that and go straight into Qt/wxWidgets.