An M14. Good for what ails you. A lot of knock down power up close, accurate at long range. Good for people, good for hunting as well. You have to figure, during the zombie apocalypse, you might not always have time to go to the grocery store.
the rapid fire automatic shotguns would seem to be best against zombies. 400 round per minute of 12 guage buckshot loads would take care of most zombies even if you don't aim very good.
A snub-nosed .38 and a 9mm Ruger, but a good machete is more fun with slow-moving zombies.
Metalstorm grenade launcher. <br />
And a good strong fence.