Its popular in zombie lore to grab a few of your homeis and get some guns and all load up and go to a mall or walmart or other large retailer of your choice,

But are these places really good areas to defend?, or death traps

First lets look at malls,
Everyones got it in their heads to go to a mall to hide from zombies, trust me, you wont be the only guy showing up there. so now you have a mall full of everyone who thought the same thing as you, this could be 1,000 plus people or more, anyone of them could be infected, you have only the food at fast-food outlets in a food court, and most of the nonperishables will go bad after a few days of no electricity. Limited sanitary facilities, you lose power and you lose water pressure, toilets don't flush, sinks don't work, the health hazards are endless, Not to mention you have over 1000 people who all have a different idea of what to do, without leaders to maintain order the mall would descend into anarchy, increasing chances of someone slipping up and lettings zombies in.

Walmarts/Grocery stores

Also not a good idea, for the same reason, everyone would be going here. The only reason you should be going near a wal mart in a zombie infestation is too loot it.Because i assure you thats what everyone else will be doing, if even if you do manage to get there first and fortify it you'll be fighting off both Z's and the fellow living, lets face it, the general population isn't gonna let 10 people sit on enough supplies to feed and arm a whole town.
If you choose to loot, walmart is a good place to go.
I recommend You hit the camping section first, you want Flashlights,Tent,Possibly a portable stove and gas,any dehydrated camping food you can find,sleeping bags,water purifiers

Don't waste time on the guns, Most On display have trigger locks, so unless you find the keys your not getting any guns. Focus on the ammo,
In addition to the dehydrated food certain non perishables and some canned food from the grocery section wouldn't hurt either.

The pharmacy.
Many people underestimate the importance of medicine in a Z war
Stock up on everything from pain killers, caffeine pills, to anti-biotics. bandages, alcohol. Needles and thread for stitches would be good too. you'll be living outside a lot, your bound to get sick, or hurt, and infections can bring down a man just as much as any Z.

Most importantly, once you do your looting LEAVE! too many people in one place for too long will draw Zack, why fight him by yourself when you can run away and join the rest of humanity wherever they resettle,

well thank you for listening, I'm sure there are numerous spelling errors and things I forgot, but I leave this topic open for debate on the Pros and cons of the mega marts and malls