Obviously I'm going to go with one of my favourite gaming series here, Gears of War has some seriously satisfying weapons that only get better when taking them in to multiplayer. Whether it's chainsawing an opponent with the Lancer, frying a whole team with the Hammer of Dawn or simply bodying someone with the Gnasher shotgun. Top pick though goes to the Torque Bow, sticking that and knowing the enemy has that split second of knowing they're fucked is brilliant... and getting a headshot with the weapon is simply joy.
Second choice is just how good simply throwing an Axe felt in the last God of War.