Do not get a fat tire, trust me. They're designed for soft conditions like snow and sand. If you're a commuter or single track junkie, the fat tires will slow you down and make you work harder because of the added centrifugal weight and friction. If you're worried about traction in loose terrain (shale rock/loose dirt) there are plenty of tire options out there for you for your average downhill/freeride/cross country/any other discipline you can think of bikes.