Surprisingly, it's not Alcatraz, at least according to The Bold Italic's Jon Korn. But, after consulting Jon Hurst, creator of the short film When the Zombies Come (one of this year's Sundance short film debuts), Korn does pick a few spots in San Francisco where you might stand a chance against the hordes of undead. It turns out that Dolores Park isn't a terrible place to dodge a few shamblers, but the zombies will eat the drunk and stoned first, so skip the Tecate and load up on coffee instead.
Watching Hurst's short film, it sounds like a hardware store might be the very best hiding spot, though. These guys spend a lot of time thinking about how to weaponize their inventory.