welcome to the forum. you have chosen the correct speaker.
with that size room and that sub, i would get M60's in the front, a VP150 center, 2 QS8's for surrounds, and either 2 M2's or M3's for the rear. i think its better to get direct firing speakers in the rear, rather than the the QS4's or QS8's.
you could go the M22 route for the fronts, but that is a pretty good sized room, and they might not reach the performance levels you want. definitely get the QS8s for surrounds.. those are awesome speakers.
good luck, and take all the input you are gonna get in stride. if you have been out of the HT loop for a while, you will have a lot to learn.. but the yamaha 2400 is a good start, thats a great receiver.
bigjohn
