Don't know yet. Depends on the money I have at the time if i ever make this (which is if all of it works out in the planning and testing phases). I'll use 2.5" drives though because they use less power, are cooler in both ways and save space. The total will be well over 100 or 200 GB probably.

I researched some more on the PS2 and Xbox harddrive stuff and although it would be very difficult and might not work, it seems possible to put games on the PS2 using the xbox. I might just reroute a USB connector to the back though so I can access the drives from a laptop if I need to.