Best Buy's prices are not very good. I hardly go there and when I do, the prices are far from the "best." In fact, for the same item, I found Fry's Electronics to be $20-30 cheaper which is a significant difference. I will admit that Best Buy's employees seem friendly and are eager to help. The only area Best Buy might actually be the "best" buy is in DVD's and Music CD's.
Another good use for Best Buy is to test out some new products such as HDTV's or LCD monitors or laptops.
Other than that, I would look around for better prices. It's not totally bad and they do have some deals ever so often, but on just a normal day their prices are just too marked up.