How technologies do you use to create your software?

Hello, I'm a game developer of 2 year just getting into internet marketing. I want to start creating software for myself that will help me in my internet marketing. I know how to program, and I'm very familiar with c#. What technology would you recommend I use if I want to get started in making my own software? I'd prefer the framework to use c# or a similar language

C# is powerfull enough to make useful tools when you are familiar with it.

I was coding my stuff in C# when I was on Win. Currently I am on MAC and using C++ for my tools.

I think for all these internet marketing related things, using a language like javascript is more appropriated ...
but it all depends what you are trying to do!