I'm a young guy, 19 years old, and I'm trying to learn all of these hot languages out there like C++, VB, Java, etc. Now that I have a grasp for most of them, I don't know what to do with it! Please help with following questions:

1.) When setting out to write an application, how should I determine what language to use?

2.) Why use C++, VB, Java, JavaScript, VBScript, etc.

3.) What language are most web pages written in?

4.) What language are most commercial apps written in?

5.) What are the best languages for us young guys to learn?