I think as someone has already said your best bet is just get a live CD of a few distro and try them out to see which ones are best.
You could try ubuntu, Mint and another one such as Centos and see which one your prefer.
I personally don't use windows at home now and stick with Centos but I mainly do server work but gaming would be better supported on Ubuntu or mint if this is what you want.
Best thing to do is have a play around and see what you think. Worst that could happen is that you mess up and have to re-install windows or something but learn a lot along the way