If Best Buy stills sells the titles and the SKU is the same, they will probably give you an exchange or a store credit. However, if you have returned anything in the last year without a receipt, they won't allow it. An easy way around this though is to bring someone that hasn't returned anything without a receipt with you and have them make the exchange.
I know this because I had a crap load of DVD's that I never opened. Some were purchased at Best Buy but many I got through my wife and other friends who work for the Studios, through their employee purchase. My local Best Buy wouldn't do it. So we went to the one in Burbank and they allowed my wife and I to each return $100 worth of DVD's, for a store credit of course. Some were older titles that didn't show up in their inventory system so they didn't take those back.
BTW, I turned around and spent the credits and them some on stuff in BB. From what I understand, the Burbank store is a bit more flexible with exchanges of DVD's because I think the Studio employees do this often.