It depends on what speakers you use. I tested wire gauges on my Salk HT2-TL speakers using Kimber 4VS (13 guage) and Zenwave 14 gauge Neotech EC-UPOCC speaker cables. Both sounded great, the Zenwave are slightly clearer but I discovered 13 and 14 gauge cables attenuate the bass, the Salk speakers has strong bass down to 34 Hz.
I currently use a double run of Kimber 4VS that has an aggregate wire size of 2-10 AWG cables. I used "Temple Caves" off of Mickey Hart's album "Planet Drum" as a test track. My old house had single pane glazed windows, using just the 13 AWG cable the bass was OK, the 10 AWG double run playing the same track made the glass rattle.
If your speakers don't go below 40 Hz then 14 AWG may work for you.