Hey Jules!
Well that depends on the zombies. Over the years, zombies have evolved from being slow-moving, pathetic, falling-apart, combustible and easy to kill, to being fast, agile, smart, able to wield weapons (
resident evil ones) and posses superpowers (
left4dead ones).
If you're defending against the slow variety it is absolutely no problem at all. Pick a ranged weapon (rifle, machine-gun) and a melee weapon (parang, longsword, spear). Note that the melee weapons I state as examples have a certain range to them. You never know what might happen if you choose to stick with a knife. Very dangerous, very risky.
If you're defending against the 21st century zombies, good luck to you. You need a ranged weapon (preferably semi-auto) with 4 times as much ammunition you'd probably get, a mid-ranged weapon (handgun), several knives and a dagger. Arm yourself to the teeth for this one.
Of course as with both varieties, stay in groups and look out for each other. Defend your territory well. Have a rotation of patrols and shit. Heck I don't know I haven't even gone through National Service.
But I know what works.
A lightsaber!
rock on.