speaker cable is a lot of hooey.......
Your system, and in fact the majority of systems in the world cannot resolve the miniscule differences in speaker cables that exist, if they exist at all......what everyone thinks they hear in speaker cables is either created through design manipulation of cables, creating false EQ networks, or is a psychoacoustic reaction to "changing" something in a system.
That said, Sean's suggestion is a good one....either AXON 4 or AXON 8 from Zalytron... $1/ft. or $2/ft. respectively.
Not trying to diss wire, but after you've built this stuff from scratch for a number of years, you will get to understand what really happens to electrical signals and why........concentrate on the circuits, forget about the wire. See Bruce Rozenblit's website and books.
www.transcendentsound.com
Lotsa Luck