Toys R Us, easily...
At my local, (Lafayette, LA) , the staff is incredible. I used to go to GameStop all the time, simply because their employees were so helpful and up-to-date, and 'Big Box' stores always seemed to have the rude, 'do I have to be here' employees.
But my local TRU bumped up their game so that the electronics section is filled with the same type of informative staff and personal service of GS. Toss in frequent $5 off coupons (as a TRU rewards member, it's a nice little surprise in the mail every now and then) and a ton of price drops/ Buy One Get One offers, and they are the gamer's best friend down here.