I use 12 gauge wire (cheap enough and I like the way the fatter than 18AWG looks--pure aesthetic preference).
I have banana plugs on the receiver as I find it much more convenient when moving stuff around to unplug the wire than it is to spin knobs and bang/scrape my knuckles. It has no effect on the sound at all, good or bad (at least not that I have noticed).


"What can be asserted without evidence can also be dismissed without evidence." C Hitchens