I'm right handed and have always used right hand mouse, left hand keyboard, for everything, gaming included. However, getting a laptop and not getting a mouse for it means I have to use the mouse with my left hand in gaming or switch to WASD, which I can't get used to. I don't have the patience to practise playing Halo the other way around for the next few months, and as I'm a university student I don't really have the time. Easiest solution for me, I think, is to just buy a USB mouse and connect it to the laptop, return to what I'm used to. I need to anyway, the Halo deficiency is really getting to me now (trigger finger starts to twitch...).