Haru's got it. Here's how I do it, which mostly follows the rulebook-
-Athletics: Catch-all defense. You can use this to defend against everything. No attack trapping, and stunts/powers that give it an attack trapping tend to be sort of broken.
-Fists: Attacking with your body. Fists, claws, tail, horns, etc. Found on horrible monsters and martial artists. Can be used to defend against melee attacks.
-Weapons: Attacking with a weapon. Swords, spears, axes, lightsabers, chainsaws. Found on things like Sidhe Knights and Knights of the Cross. Can be used to defend against melee attacks.
-Guns: Attacking with a gun or a bow. Ranged weapons. Handguns, rifles, crossbows, longbows, laser pistols. Found on cops and military guys. Pretty typically a Pure Mortal skill. No defense trapping.