Firearms in the zombie apocalypse are conditional. Is it one zombie? Two zombies? Sure, bust out the melee weapon and chop 'em down. But a bunch of zombies? If you wake up and find your hide surrounded by a swarm? That's when guns come in. Sure, it's noisy, and you'll attract more zombies. But noisy and on the run beats eaten.
Hence the two handguns I referenced. The Medusa can fire pretty much anything in the 9mm/.38 range, from automatic pistol ammo to .357 magnum rimmed cartridges. The omnivore of pistols, if you will. The Grendel P30 uses a fairly common cartridge that is both fairly quiet and with a reasonable enough penetration power so as not to bounce off the skull (.22 Winchester Magnum), and holds 30 rounds in a magazine that's fully housed within the grip.
Of course, then there's the whole fast zombies vs slow zombies problem, and the alien space bats modifier that can throw it all out of whack.