Best Buy- love it, where I get almost all my games, because I still have GC unocked....pair that with sales and new games can be dirt cheap.
Target- good for household items, clothes, food, etc. I go to Target a couple times a month.
Walmart- A bastion of filth. I usually feel the need to take a long shower after entering. They do carry some obscure titles though...but they aren't cheap so I skip 'em. I go maybe 1-2 times a year to check the sales shelf.