Retro City Games is the place to go for pretty much any previous-generation console needs.
Doug and Nicole are extremely helpful and I have found myself going to the shop at least once a week ever since I found out about it because they have such a great selection and because the atmosphere is so inviting.
I highly recommend them both for their customer service being leaps and bounds greater than every other retro-gaming shop in Las Vegas and for their always-changing selection of games and merchandise, which you don't really see too many of the other retro stores doing.