Ok gonna play devils advocate just to point out the other option no one recommended...Run single ended to main speaker amps and balanced to the subs. Reason: the run to the main amps is probably much shorter due to the amps being closer to the preamps...if your amp(s) are basic stereo amps then they are probably close to the preamp with a long(ish) speaker cable run. If you have monoblocks for the main amplifiers and position them at the speakers, that is a different situation and using the balanced outputs to the mains probably makes sense. Obviously whichever set of outputs is leftover get relegated to subwoofer duty. I'll never do monoblocks due to the extra expense and the extra space gobbled up by extra boxes. Stereo amps are my preferred poison. That said, they will be as close to the preamp as possible and will have very short unbalanced cable runs to them. The subs may have to end up ANYWHERE in the room to sound good and so I reserve the balanced connection for them. Your mileage may vary but that is my approach and it works very well indeed.
My current system is a bare bones system with nothing but unbalanced outputs and I am not disappointed much because the noise is completely inaudible. I live in a noisy apartment building and could probably tolerate a noise level in the amp that many people because of their living situation find completely intolerable. What I have works fine where I am now. If I indeed ever get to move back to my home, the current system will get relegated to bedroom use or something equally undemanding. I cannot wait to be in my own home again.
