Qt

I want to learn Qt to have a decent standard library for C++. Before I start, I want to hear your opinions. Is Qt any good? Alternatives?

Qt is a pretty nice framework for C++. However, if you're writing something with Qt purely for GUI purposes and you don't care much about the UI's performance, then try using something else. Writing GUI code is fucking awful in just about any language, but it's a lot easier to do in a managed language (like using C# for the GUI and calling procedures from an external C++ library).

Personally, I use either Ruby or C# to develop the front end, because I've found that it takes forever to meet client's GUI specifications using native code. Most of my applications aren't very UI-heavy, as you can probably tell.