Let's see... Zombies. Lots of 'em.
Weapon: I'm hardly in shape to do fighting, and not sure about being able to use a gun. Still, assuming plentiful ammunition, a standard shotgun would be a Nice Thing. If we're going melee, then ability to do damage at reach is key. Perhaps one of those gizmos that uses a gunpowder charge to drive a steel rod into concrete? That'd pulp zombie brain real good. Reaload time is a bitch, though. I'll go for a sharp iron rod: can swing and break bones, or -thrust into the head. I'll want my LARP shield, though.
Music: Toughie here.. want something good and powerful, that can drown out the moans of the living dead and provide inspiration. I'd probably slap in The Who, The Beatles, or U2 and be done with it.
-Living - Any Marine who's a better shot than I am. Jackie Chan. Teller (see '&Teller' at http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=28947955
Dead - Bruce Lee.
Weapon: Flak Cannon from Unreal Tournament. Lightsaber (I *probably* wouldn't cut my own arms off...). Covenant Battle Rifle from HL2.
Music: See above.
Person: Mace Windu, Gordon Freeman, or Gandalf. Or Superman, if we're just gonna go cheese-fest.