What Programming Language is best for Mechanical Engineers?
That depends on the application and what operating system you wanted to run it on. I'm currently learning delphi which is a visual programming language which means that visual tools like windows, buttons, drop down menus etc are available for you to use. If you want to write a program that runs like a windows application then you should use a visual programming language. Some visual languages are easier to use than others. Delphi seems to be the quickest way to develop professional looking applications.
I'm also impressed by java because it is so modular. It's also free, (you can download a free compiler from Sun Microsystems). Java classes (units of code) can be easily re-used in different programs. Java seems to be specifically designed to make code re-use easy. The drawback of java is it tends to run slowly, which could be a problem for numerical analysis.
Microsoft made a product called visual J++ (or visual java), which in theory could be really good. However Microsoft seems to see Java as a competing technology and are unlikely to develop this product much.