Best Buy and Circuit City are madhouses. I really think Sears would be more of a madhouse than Radio Shack, but you never know.
Alot of this has to do with your location. When we'd do BF in Williamsburg, VA, you had to be there about 1.5 hours early and you were in good shape. In Frederick, MD, you have to be there 4 hours early, AT LEAST, to get in good shape.