I went for
the 2 TB one which is twice as big as what we need.
So after this drive arrives we will have three dives connected to the Airport base station for use with TimeMachine. One 320 gig, one 1TB and one 2 TB.
Now all I need is a Flux Capacitor so that I can learn all the winning sport and lottery numbers and become so rich that I can have my own liar in a volcano protected by sharks with lasers mounted on their heads, groovy man.