Best source for automotive wire

Doing a lot of wiring on my sons car but to be honest it's crap. Once I get it all figured out electrically, I plan on "doing it right" with proper GXL rated wire and the right gauges etc. I know I can buy stuff, like what crackedback sells, but part of this is an exercise in learing to build harnesses etc. I'll do it with a harness board etc just like the grown ups do.

Going to make a relay/distribution panel to cover

fuel pump
headlights
Turn signals
ejector seat

Basically trying to keep the high current stuff from passing through the firewall.

Who has a good source for this stuff and what colors should I focus on..

Off the top I'm thinking....

color gauge(s)
---------
red 10,12,16
black 10,12,16
brown 16
black/white 16
tan 16
white 16