I worry about some of you and your lack of realism.
I'm pretty sure I've read something about people getting tanks and fully auto weapons... Face it that's unlikely...
In a zombie apocalypse I would probably prepare ahead with a fence or something as simple as that. Zombies don't really shouldn't use their brains so a fence should actually be good enough for a temporary barrier.... Plus your neighbors won't think you're crazy... And most people talk about going and getting unneeded supplies... All you really need is some extra pairs of clean clothes, a weapon (preferably not only a melee so you don't have to risk infection), a good backpack, and some friends who probably won't get you screwed over. Shotguns are debatable because if you have a good choke on them they can actually shoot a little ways, plus they have some power in them. For instance in a zombie apocalypse I would just grab some clothes, a backpack with my wilderness survival gear, my .308, a .45 W/ buffalo bore(insane recoil but serious power), and a 12 gauge with a good hunting barrel and a sawn off for searching building for supplies if necessary(all of which are available to me). I also strongly suggest in having food storage, livestock (chickens for example), a green house, and some soil, seeds, and a lot of water. And you want some friends along to help out, and you want to get moving as soon as possible so don't waste time getting armor and stuff. If you can use a gun or bat or something use it and stay alert. Keep watches at night. It's that simple. No detours to stores or anything. Just grab some essentials and get moving. That's the best thing to do.