Now, we all know, we have to kill zombies, but the question should be, "how would be the sweetest way?" personally, I'd think it'd be charging into a mob with a chainsaw, then when that stops working, pulling out a pair of power sheerers and chopping the fuckers apart.
if it tries to grab me from behind, ill use a takedown move and then crush its face with my boot. this will take about 10 seconds, tops. i tried it on a couple real people, didnt actually crush their faces, but asked them to try to bit me as much as they could, they couldnt, and they have all their motor skills.
Napalm. Or another medium scale incendiary of some sort.
I like to blow shit up. I'm on my way to getting my operator's license to become a certified pyrotechnician, so it'd actually be REALLY cool for me to be able to construct a lethal shell and set it off in a large group of zeds....a pile of zeds AND a pretty shooting star with rainbows? Score.