What does a petabyte of data look like?

Today I saw my first petabyte system. A SAN composed of multiple cabinets, each one with 225 disks of 360GB each.  Wow.   Even more impressive was the size of it all - it could easily fit into the kitchen of my tiny Manhattan apartment.

Any bets how long it will take until we all have petabytes sitting on our desktops?  3 years? 5?  10?