A tough question, but an excellent thread!
First off, I'd have to go for my Mossberg 500 shotgun, strapped to my back. While a 20g, the right ammo would allow sufficient capabilities, and being smaller shells than 12g shells, would allow me to carry more ammo.
I could carry three pistols (I've done it before when I was too lazy to make two walks to my storage room), a S&W Model 66 in .357 Magnum, my SA 1911-A1, and a SA XD-9 SC. Chances are the SC would be in a compartment in a backpack. The backpack would allow me to carry an ample supply of ammo, medical supplies, batteries, twinkies (they last forever, after all

), and a couple of bottled waters.
Of course, a flashlight would be required. A 4D MagLED would be on the backpack, strapped in the drink slot, for bright light, or a backup blunt weapon. In addition, a Fenix P1 would be my choice for more frequent use.
My SOG Seal-Pup would be on my belt, as would one of my folders, for utility purposes. All this on me would allow two free hands, in which I would carry a katana. Not to seem like a mall-ninja (If you don't know about mall-ninja's, Google it, and be prepared to laugh), but it would be suitable for removing the zombies' limbs. It allows a good reach, and has great offensive AND defensive capabilities. Granted, I'm not trained, but zombies aren't really the fastest. If it's not an option, I'd go for a machete in one hand, and a khurki (spelling?). A blade weapon (or a pair of them) would be a must, to avoid the dependance on ammo. I'd think that I could manage the katana, though.
Finally, in the event that it doesn't all work, and I'm doomed, I'd fashion a zip-gun, with a single .44 Magnum bullet, for a quick death. If you don't know, a zip-gun is a crude firearm often crafted by people in prison, usually single-shot, for smuggled bullets. Being that I have the option of preparation, mine would be more effective, to make sure that fires when I need it to. Better a quick death than being eaten alive.