A good friend of mine manages a (carrier) retail store and I recently had the opportunity to tour it and there's a lot of great things that Best Buy can learn.
They only have two computer-based point of sale systems for the entire store, for cash transactions, and I know this may seem impactical in a store like Best Buy but it would be interesting to see what would happen if you had 1 computer-based point of sale system for every 3 tablet-based ones. The idea being that customers can checkout anywhere in the store and it also creates a more "in-the-moment", personable shopping experience too. With the move to mobile payments and cards at an all-time high, this also makes more sense, logistically. The 1-in-3 rule, also ensures that certain departments like Customer Service and Front Lanes still have some computer-based POS systems too and that could be where customers paying with cash or check go to checkout, but to be honest & fair a majority of transactions nowadays happen via plastic or mobile payment.
The other cool thing I saw here is that they have kiosks where you can pay your bill. So instead of sending customers to customer service to pay down/off their cards, you could simply have self-service kiosks at the front of the store where customers could do this on their own.
Finally, the store has a queue system where you can check in and tell the person what you're there for and your name shows up on TVs all around the store so you know you're place in line. I don't think that this system (in its entirety) is right for a store as large as Best Buy, but it would seem like you could take the "Book-a-Blue-Shirt" pilot (for those not familiar it allowed you to check-in, in-store via the Best Buy mobile app, and schedule an appointment for assistance) and improve it by adding beacons to the store where employees can know approximately where in the store a customer is, based on proximity to a beacon. Customers could use the app to see their place in line and they would get a push alert when it was their turn.