I'm hoping that CoD4 is still pretty popular once it comes out for my gaming platform of choice. I still can't stand FPS games on consoles, so I'm waiting on the OS X release at this point.
It's a shame more console games don't allow a keyboard and mouse. I've played UT3 on a PC and PS3, and the experience is nearly identical since the PS3 version supports a USB or Bluetooth keyboard/mouse. The only difference is that the PS3 version runs at a 10% slower rate, to allow people using a controller to deal with the normally very hectic gameplay UT offers. Unfortunately that change made it impossible to do PC-PS3 play though.