as per Bill, you may/no doubt will need to delay the rears, the reason being: imagine a circle, and a dot in the middle of the circle. The dot is your seating position, and so if the centre speaker was placed at the 12 o clock position, the front left at 10, the front right at 2, the rear/surround left at 8 and the rear/surround right at 4, then the sound from all the speakers would reach you in the middle at the same time. In reality though, the front speakers sit on the same horizontal plain as the centre speaker and so are further away from you than the centre speaker, and you usually sit right next to the wall where the rear speakers are hung, hence the DVD player can delay the rear speakers by a matter of milliseconds to emit sound at the same time as the sound from the front speakers reaches you, and the amount of milliseconds you set depends on distance, of which the DVD player guide should tell you this ie so 5m away = 14 milliseconds etc

Also, place the sub behind the sofa that you sit on, some say install the sub by the TV, this allows you to hear the bass. I say install it behind you, you dont just hear it, you -feel- it much better and more cinema like!

Enjoy!