My weapon of choice would (probably) be a suppressed, fairly high powered pistol (maybe a .40?), one that's reliable and fairly easy to clean/take care of. Most handguns are small, lightweight in comparison to rifles/shotguns, and therefore, easy to bring along with your other supplies. Their range isn't usually the greatest, but unless you're giving some sort of covering fire to someone, you shouldn't need to shoot more than maybe a couple hundred yards/meters. If it turns out that a handgun isn't the greatest choice for whatever kind(s) of zombies we'd get, then I'd probably take a hatchet or some other kind of axe.