Consider how buggy
WinXP is now at, how many Gb is the install? 2Gb? IF their "operating system" needs 1Tb, how many bugs will that be? hmmmm.
Longhorn. Isn't that supposed to be the one that documents everything you do and has all the security stuff with the lightsabers and the vwwing, vwinng, *vwwing". (Sorry, Professor Frink relapse).
So maybe it needs 1tB to store every keystroke you ever do, every move on the internet, etc. and sends it all back to M$. Don't worry though, every month, M$ will go over your hard drive and rid all files that don't directly pertain to running Office.
Have fun suckahs!!