Hi, 'ablatt'.
I'd suggest a FireWire drive, specifically an Oxford based one. Good examples are the LaCie d2/d3, Maxtor OneTouch III, Wiebetech or most OWC units.
Yes, you can copy the internal disk to the external, and you simply start up from it and copy back with SuperDuper -- or, if you have lost the internal, you can even run from it and continue working. Much better than Windows...
