I've been looking at & learning the QT Library, and ... wow, it's nice. :)
At first, one feature bothered me a bit. QT generates "MOC" files. MOC stand for meta-object compiler. If you write any classes that use QT's signal/slot calling system, you have to run your header through the MOC, compile the output, and link it with the rest of your object files.
However, after spending a few hours writing a kickass Makefile, all of that is done automatically.
QT 2.2 now (maybe before, and I just didn't notice?) has a QSocket class which abstracts TCP/IP sockets. I whipped out a nice (though, simple) plaintext chat application in a single day.
Now that I'm lovin' QT in Linux, I wanted to see what's involved in using it for Windows. Well, crap, it's more than $1000 (US) per developer license. That's what they do. They write a great GUI toolkit, hook the poor, innocent Linux developers, then charge them if they want to actually make their programs available to the masses. I mean... really. I've seen MFC. I've seen the beautiful code that results from using QT. After seeing how it's done RIGHT, I don't know if I'll ever bother to learn MFC.