In this video I compare the different hard drive options for the Xbox One and the Xbox 360. The Xbox One will have a 500GB hard drive and will offer support for an external hard drive. Since the games on the Xbox One need to be installed to the console an extra storage device will be needed if you are planning on buying a lot of games
My Xbox 360 Collection
https://www.youtube.com/watch?v=dQ6UboyzmD4
30+ Xbox 360 Games Installed On My 250GB Hard Drive
https://www.youtube.com/watch?v=FaS_zuxN7VM