There's one distinction that I didn't make clear... I'm not trying to learn C++, I'm trying to learn
more C++. I'm at that awkward stage between being able to get an A on every assignment in college and being able to write something useful.
I'm wanting to write a personal development application that allows people to use several different systems. I've noticed that there are people out there who use Linux and are unable to use any of the existing applications out there because of compatibility, so I want to add cross platform support into it at the beginning. If that means that the code has to be open source because I'm using some GPL code, then that's fine.
I also want to be able to add new modules, different management systems, without having to recompile the source. That way, a person can add in their own, or customize one of the built in ones, without the headaches of figuring out someone else's code.
Thank you all for your recommendations. I think that I'll go with the GTK, but of course, there is a bit of research to be done before the code is actually in place.
If I need to, I can still fall back on C#.