You are in a mall when the zombies attack. You have:
1. one weapon.
2. one song blasting on the speakers.
3. one famous person to fight alongside you.
Weapon can be real or fictional, you may assume endless ammo if applicable. Person can be real or fictional.
1. A high elevation location and a high-pressure molasses hose. (Maybe not so very lethal. But very entertaining.)
2. I'm still a big fan of the Resident Evil soundtrack. (newbabel already chose the Muzak version of "The Girl from Ipanema", and unfortunately, the awesomeness of that just can't be matched.)
3. I'm gonna go with Ellen Ripley, here. Just because she's got a spaceship from which we can nuke the site from orbit. (It's the only way to be sure.)