I say 2 is fine, not all three.
I personally would get 360 and PS3, but i never liked NINTENDO for my own personal reasons so i would never get all three consoles.
PS3 is my choice, and i want a 360 because it has some pretty good games i would want.
So i would say either 2 or one. 2 is better because if one breaks down u can still play video games even though the other one is getting repaired. I wish i had a 360 because currently this is my case....MY PS3 BROKE DOWN!!!