I personally hate Best Buy with a fiery passion, but I still buy from them because they have severe monopoly over my local stores.
I bought 5 macs from Best Buy that were actually broken. Then one the ones I returned, they never sent it back to the retailer or wiped it, so they re-sold the iMac with the broken fan with all my info on it to some person for 100 bucks off. I get an email 2 months later that says "ohhhhh I bought this computer at Best Buy, and all your info is on it, whats your password?!!"
Needless to say I called Best Buy and gave them hell. They know me by name now. Everytime I walk in I see more people at the returns than at checkout. I've also gotten DVDs that didn't work, a game box with NO GAME, a DVD player sold new but was obviously opened and was missing cords and a remote, and I bought a TV there that malfunctioned and would randomly switch to Telemundo.