Wellll, Joe... get ready for another "mixed cabs versus matched cabs" thread.
Me, I would gladly mix cabs but only if I was using some kind of crossover to separate frequencies. Otherwise I'd go with the 6x10.
Me, I'm aiming for a couple of 2x12s. We'll see how that works out. My two 2x10 rig wasn't cutting it in terms of volume and tone.