Sub: I use a PB-10NSD in a 13' x 18' media room and it rocks the room at less than 50% of available gain! Buying any more sub, although fun, is not necessary for either HT or music, although a case for eventually using two PB10s can be made for other reasons.
If your room is not on the ground floor, I use and recommend getting an Auralux Gramma isolation platform for the PB10, it will help keep the bass in the room and out of your walls, floor, other rooms, etc. Link below:
Receiver: The 465 might be a little light on power, and does not have any pre-amp outputs should you want to add an external power amp in the future. To get pre-amp outputs, you would need to get at least a 665. This may save you money over the long-term.
Have fun,
XEagleDriver