If it were me I would wire for 7.1. It cannot hurt. Is it worth it? Maybe in the future but it always sucks to wire short and then have to go back in. Get your 5.1 speakers set up and when you are ready you can order more speakers. If you order from someone like Axiom you can return them if you cannot hear/feel the difference between your current 5.1 and a 7.1 system.

Regarding the QS4's. I have them and am kicking myself for not going with the QS8's. IF you are going to listen to music in that room you may want to think about the M60's. I have both the M60's and the M22's and the M60's are much nicer to listen to movies on along with music.

Good luck and when it is all done, send pics!