Windows can't run without a registry... The Enterprise edition of Vista images we're pushing at work are 22-25 GB, too big for the 16GB sticks available. 480 MB speed for USB is faster than SATA 2, but that's just theory as usual. Portability... you need the same hardware on all machines to get that magic to work. Damn Small Linux at 50mb is cool to use as a diagnostic tool, no CD's to carry..........Take a spare drive and install Vista as you will, create an image with Ghost or Acronis and push it to your USB stick and test, first hand testing is ALWAYS the way to see if what you've got is what you want!