I've never thought twice about going to a Wal-Mart when it is convenient (case in point, my lady lives in Birmingham and has a Super Wal-Mart right around the corner). However, where I live in Reston, VA, the closest Wal-Mart is probably a good 8-10 miles away in Sterling. Not worth the drive to save the few cents.
Blue, I'd be curious to here a bit more about the general "locale" of that Wal-Mart. I have been to Wal-Mart's in a variety of neighborhoods and there are definitely differences in the cleanliness, staff friendliness and general "feel" of the store (although, I will admit to never having noticed an odor as you did. Maybe just a bad B.O. day for a few in the store, as I was privy to someone's bad "funk" in my neighborhood Best Buy (and some might argue this is a "good" area fwiw - not much as far as I'm concerned). Stores seem to be filled with more funk around the holidays anyway (people sweating too much as they stress over gifts).
I have been to a Wal-Mart in Salt Lake City (in the downtown area) that would knock your socks off (The design included brick and was obviously trying to appeal to a different clientele), some great SuperCenters in tulsa, birmingham, nashville and destin (florida). On the other hand, I've been to some that were not as pleasant also in Tulsa and Birmingham and Montgomery (worst I've visited). But, in comparison, I would have to say it was more than just the Wal-Mart but those areas of the city in general.