I used 2 x 2 and think it is fine for most applications. You would be surprised how quickly the channels fill up with excess wires and power cords. Good luck with your project!
LOL, this is what happen when you don't have a fish room and try to squeeze every equipment possible under your stand. No choice, wife don't like things outside of the tank.
Finally got around to fixing the wires in my stand. Not the most fancy set up but it will get the job done for now until a new setup. Got the peg board idea from lowbudget and Terefel (Jeff) hooked it up with the wire chase. Some before and after pix