As I believe has been mentioned before - the most common language you're going to see in the industry is C\C++. So having a good handle on that language is a must.
However - it's much easier to get a project up and running with something like C# (using XNA) or Python (using something like PyGame) where you don't have to deal with as much of the nitty-gritty as you do with C.
Personally I would be more impressed by someone who was able to present me with a finished game, no matter what language it was written in, as long as it was fun and reasonably polished. Then we can talk about your proficiency with certain languages
