Shotgun easily. If a zombie apocalypse occured and I had my pick of armament, I would choose a shotgun to hold, with two pistols in a dual holster, and a sniper rifle in a seperate carrying thing on my back. Long, mid and short range weaponry, and I'd have twin swords also attached to my belt. A veritable killing machine. Plus, given I've known how to use a gun, and fired them myself, ever since I was 14 years old (surprising since I live in the UK), I know how to fire and exactly where to aim to kill a man (or zombie). Not that a shotgun really needs much aiming, just point and shoot. No way will I die in a zombie apocalypse...