I HATE BEST BUY's return policy antics. They say you can return stuff within certain timeframes and guidlines, but then hassle you even when you fall within the guideline! They are morons, and have horrible cust. serv.
On the open box tip, BB usually sells OB products for retail - 10% as stated, and will not negotiate on that, unless in extremely poor condition merch. Circuit City on the other hand has much better OB pricing, and if you get the right manager, you can get them to knock it down a few more bucks, especially if you offer to buy their extended service (which you can return within 30 days if you didnt intend on buying it, while keeping the OB price that the mgr. gave you).