My husband and I just purchased a Yamaha RX-V673 to go along with our 5.1 Definitive 600 surround sound speakers. We mostly watch DirecTV channels (sports, TV shows), not DVDs or anything like that. What is the best sound mode to leave the receiver on? Straight? Sur Decode? I'm not even sure what all the options do, but they all sound different. Is there a best one to leave it on when just watching regular tv? Thanks so much for the help!