I'm not a fan of chainsaws as anti-zombie weapons, despite their use by the great Ash. But this variant of the chainsaw intrigues me. It's a small chainsaw mounted on a semi-automatic rifle as a bayonet. It would make the rifle absurdly heavy, but it would also provide some safety in the event that a zombie gets within four or five feet -- when the rifle would become ineffective.
I'm rethinking the Max Brooks-endorsed M1 carbine as my anti-zombie weapon of choice. .30 carbine ammo is rather unusual, and in the event of a Stage 4 zombie apocalypse, I wouldn't want to be scrounging around for it in vain.
Neatorama readers, what is your preferred anti-zombie weapon?