Hi I am venturing into the world of Home Cinema for the first time, and I have already decied on some of the components - a 42 inch plasma, and KEF KHT 2005 speaker system, and pioneer 747ai dvd player. Now comes the hard part firstly, what is the difference between a receiver and an amplifier? Ideally I would like something that is good for music and movies, so I thought the Yamaha 630RDS would be a good choice. is there any others that may be better, but in the same price band? thanks very much for your help!