Not 'probably'.
Ms is also aiming at making their 360 controller the #1 controller for pc gamers. They will win there, trust me, because tehre aren't much great pc controllers.
The whole '360 controller can be used on your pc' is old news. You can't use pc controllers, imo, because they aren't configured for the console. Just my own though, but it would also be pretty useless. And god I hope you can't game with a mouse and keyboard. Then again, the game would have to go through the time to make mouse support native, so I think we are safe there.