Your profile doesn't say where you are from. In the USA, the best price for pretty decent wire is Monoprice. I bought mine through
http://www.cablesonsale.ca/I went with the 12 gauge as it was on sale at the time, and pulled an insane amount of cable. I pulled two pairs for the Center, Surrounds & Rear Surrounds. four pair for the Fronts and single pairs for front and back heights. I figured the heights were just in case I decided at some point in the future to look into that Atmos/DTS-X.
Best of luck with your HT build. There are quite a few of us here that recently have built and I am sure if you have any questions not only about cable, but also sound proofing and design, there are lots of opinions available here
