many people want to go the wireless rear speaker route. the first thing to realize is that it isn't actually wireless. All speakers need power, normally they receive their power from their receiver through the speaker wire. this can cause problems as you will always see the wires run from the receiver to the speaker unless you put the wires in the walls. Now for "wireless" speakers there is still a CORD! it is just from the wireless unit to the speaker instead of across the room. the wireless systems can be problematic if they are not built into the unit itself.
I would and do avoid it.
As for Best Buy... it is a good place to buy electronics, though you will have a hard time finding someone who knows what they are talking about. I would avoid it as well.