A farm. I'm picturing one in western Kansas just based on my own experiences, but it's where I would go in case of zombie outbreak-- self sufficient, isolated, flat terrain for high visibility. And it's western kansas, so it shouldn't be too hard to find rifles and such. :P
Costco/Sam's Club warehouse sort of scenario seems like a good idea in the short run as it would be well supplied and more easily defended than a mall would be, but you have to consider that something like that is going to be in a pretty well populated area. If you were expecting the military to come bail you out or the zombies to all fall apart once the planets un-align themselves you might be ok, but you couldn't stay there forever. You would be able to stay there until you ran out of food, but if it became neccesary to leave you would be in alot of trouble.
And the Zombie Survival Guide is great, I haven't read WWZ yet but i'm looking forward to it.