I'm the complete opposite from you. My sensitivity is so high I can easily pull a 360 before getting close to the end of my mouse pad. I'm always a frontline assault type of guy and never snipe so it works well for me. My mouse also has a super high DPI so it's not like I can't line up a shot when I need to.
I play Quake Live close to the highest sensitivity. I barely move my wrist when aiming, and a slight flick will do a 180. Most would say that this isn't as convenient as more "sane" sensitivities, but I've gotten used to it, and play much better than I would with an average speed.