Recently, I was doing a bit of research on solid-state drives, which are like hard drives except they use solid-state technology. This would make it a lot faster, and as there’s no moving parts, more reliable (although I imagine if you hurled it to the floor or ran it over with a garbage truck it would shatter.)
USB drives are solid-state too, but a lot slower.
However, currently it’s expensive, can’t hold much information (On Newegg.com, they’re up to 160 gigs), have limited write cycles (this may be exaggerated though), and no disk cache. However, if more interest is shown, maybe they’ll be developed more and the price will drop.