I was going to power the arduino through the USB interface. The only thing I'm going to be doing is driving 6 PWM outputs and 6 digital outs, no LEDs or other devices. The 2.5W a USB connection can draw should be enough for that right?
Unless the driver IC uses <0.25W each, I won't be able to run them off the Arduino because I will be using 6-8 of them.