Buffalo's managed to cram 500GB into this MiniStation Turbo, which is a small, portable, 5400RPM USB hard drive with "shock absorbing material" to protect from unintended drops. Buffalo claims that it's got up to 30% faster transfer rates than "most USB hard drives", but chances are you're going to be buying this for the size and not so much for how fast you can get your data off of it. 500GB in your pants? Yes please. The only thing holding us back is the slightly high price of $329. [Buffalo]
Agreed. I've been keeping a mirror of my iPod (40GB) on an external and externally-powered 7200 rpm 3.5 in. HD on my desk at the office. This would represent quite an increase in space and would be much more portable... at a modest premium. It's got to be a bit of a power hog for a lappy battery, but still a very nice clean way to get your half-gig on.