I asked this myself a few months ago, before I started wiring in my 7.1 system. Axiom's speaker cable is apparently not rated for in-wall use, but I will attest that is very nice. I ended up using BlueJeans in-wall 12G for my (just completed 2 weeks ago) installation.

I bought a little Axiom bulk cable for hooking up my fronts, and I wish I got more - it's very pliable and easy to work with.

M60s, VP150, QS8 x4 ACI Titan II sub Anthem AVM20 pre/pro Anthem PVA7 amp Panasonic DVD-RP91