Small netbook with a conventional hard drive (one with moving parts).
Neoprene sleeve over it and then put it inside one of these which has more padding and keeps out water/dust:
http://cascadedesigns.com/sealline/u...sleeve/product
I use the smallest size and I have room in the case for a spare battery and a separate mouse (I hate touch pads). Great case.
Make sure that you do not pack it in a way that squeezes it, I had mine flat (horizontal) in my duffle on top of the rack and apparently had a few pounds of stuff on top of it that pressed down on it, 80 miles later I could see the outline of several of my keys on the screen from the screen touching the keyboard for 80 miles.