I'm an undergraduate Software Engineer student, although I've decided that pure programming is what I want to do for the rest of my life. The thing is that programming is a vast field and although most of its aspects are extremely interesting, soon or later I'll have to choose one (?) to focus on. I have several ideas on small projects I'd like to develop this summer, having in mind that this will gain me some experience and, in the best scenario, some cash. But the most important reason I'd like to develop something close to “professional” is to give myself direction on what I want to do as a programmer.

One path is that of the Web Programmer. I enjoy PHP and MySQL, as well as HTML and CSS, although I don't really like ASP.NET. I can see myself writing web apps, using the above technologies, as well as XML and Javascript. I also have a neat idea on a Facebook app.

The other path is that of the Desktop Programmer. This is a little more complicated cause I really-really enjoy high level languages such as Java and Python but not the low level ones, such as C. I use both Linux and Windows for the last 6 years and I like their latest DEs (meaning Gnome Shell and Metro). I can see myself writing desktop applications for both OSs as long as it means high level programming. Ideally I'd like being able to help the development of GNOME.

The last path that interests me is the path of the Smartphone Programmer. I have created some sample applications on Android and due to Java I found it a quite interesting experience. I can also see myself as an independent smartphone developer.

These 3 paths seem equally interesting at the moment due to the shallowness of my experience, I guess. I know that I should spend time with all of them and then choose the right one for me but I'd like to know what are the pros and cons in terms of learning curve, fun, job finding and of course financial rewards with each of these paths.

I have fair or basic understanding of the languages/technologies I described earlier and this question will help me choose where to focus, at least for now.