There are several other posts in which folks have shared mostly positive experiences regarding carry in different Wal-Marts. In fact, the incident at the Hampton Wal-Mart, one in Lynchburg, http://opencarry.mywowbb.com/forum54/173.html and one I had in a rough part of Richmond a while back http://opencarry.mywowbb.com/forum7/241.html (about halfway down the page) are the only significantly negative reports that I have heard about. It is very unlikely that anyone will "freak out". In fact, unless you act in a manner that calls attention to yourself or to your weapon, most folks probably won't pay any attention.
It is my understanding that Wal-Mart's corporate policy is to follow the laws of the jurisdiction where their stores are located. Since OC is legal in VA, WM corporate doesn't have a policy against it. Sometimes you may run into a local manager that doesn't know or follow corporate policy, but they will normally back down and apologize after corporate calls them.
I've OC'ed at Wal-Mart dozens of times in Mechanicsville, several times in Waynesboro, once or twice in Madisonville, KY, and a couple times in Laramie, WY, all without incident.
Dress appropriately, carry yourself in a normal, professional manner, and you shouldn't have a problem. If you do, be cooperative, not argumentative. Do as they ask, but get the name of the person you dealt with, and contact corporate with an accurate report of the incident after you get home.