Ugghh... don't use Silverlight. Stick to Flash or Flex-- they're much more widely distributed, and much more widely supported (because they've been around for so long).
Just to give you some insight into the game development world-- if you work for a company like EA or Blizzard, you'll be coding almost exclusively in C++ for the game engine. For online framework, it'll be a combination of Python, PHP, and MySQL.
Right now what I'm studying is information interfaces and data visualization. It ties in very nicely to game development. =D
Ghost