At roughly a buck a foot, the Canare 4S11 is pretty decent stuff for HT. it supplies my center and surrounds.
My mains use SR Sig 10 active x2 biwires. I'd like to be able to run all spakers with the Synergistic cable, but it's cost prohibitive, for me anyways.
Each time I've stepped up in cabling with 2ch audio I've noticed improvements. Not as much with HT though. I'd remain a bit more modest in my designs on going all in on pricey speaker wires there.
Instead, I'd suggest doing as I've done. Add something really nice to the mains, and maybe even the center if funds permit... and do as required elsewhere.