Joel,
MCM electronics has a variety of wire. (
www.mcminone.com) We use the "zip" wire that is paired red and black wires bonded together. They can be separated by "zipping" them apart. I suggest #10 for all high current motors regardless of what breakers you use.
We use Anderson Powerpole connectors when needed. They are available in a variety of colors and can snap together to form multi contact connectors. You can purchase them through Terminal Supply or West Mountain Radio. At West Mountain you can also purchase a really good crimper for these contacts.
I also recommend you position the Victors close to the motors so you don't have to add a connector in series with the motor leads. Then you cut to fit the wiring from the breaker panel to the Victor and use the existing motor wire to the Victor. We use a bent pushon male adapter with a screw mounting hole. These are available from Digikey. We add them to both sides of the Victor and then use normal pushon females for connections. This allows us to swap out a motor or controller that has failed without tools.
The house wire suggested before is also available at most home centers like Menards or Home Depot and you can buy it by the foot.