The most important will be the front 3 and the sub. The front 3 will determine what your power requirements for the avr, and the room size. The 7 series are descent speakers, but the 5 series may work as the surrounds. Unless you need 7.1, 5.1 will do the trick most of the time. You can always start out with 3.1 and have the wires run for the rears; to be installed/purchased at a later date. If your are installing a display on the wall,make sure to run at least the CEDIA spec wiring.