Here is some of what will be pluged into the usb ports.
Asus usb wifi
zonet usb bluetooth
keyboard (could get a ps/2 if need be)
PS2 to usb adaptor (using the analog as a mouse)
1-wire to usb adaptor (temp sensors)
IR to usb adaptor (for remote control)
Memory card reader.
Actualy that is all I need plug in at this point but it would be nice if I had one free port to jack in my pen drive and such. I would guess the wifi and bluetooth are the two power suckers in the list.