K/B and mouse isn't going to be that unfair if you reflect
Bungie has stated that they want every XBOX live game to be as evenly matched as possible. That means that they are going to match up gamers on the basis of their statistics. Therefore all the people on Live with a K/B and mouse are going to inevitably end up playing one another if they consistently dominate. Casual gamers who log on just for a good time with their S-controller will probably end up playing someone with an S-controller. If you want to be on LIVE and be at the top of the ladder, no doubt you'll need a M+K. But the people who play enough to get to the top of the ladder are clearly going to be the minority, and I suspect will have no problem spending $30 dollars on an adaptor. If you do play well enough with your S-controller to end up in competition, good for you. But casual gamers with their S-controllers will probably rarely ever get matched against someone who's hardcore enough to have actually gone out and bought a $35 adapter and whos prepared to invest the time to make it high up on the ladder. This will produce a natural segregation of Live into K+Mouse players and S-controller players, much as baseball is divided into the Majors, Minors, AAA, etc. This is why S-controller players shouldn't worry too much.