Ditto, don't think I'd pay for the design. There are 80gig drives for the same price.
I have a usb-to-ide connecor and use an old internal drive (not so pretty but cheap) and it works just as you suggest - plug it in and XP sees it as another drive. I think you need to be win 98se or better for usb and XP manages without additional drivers.
There may be other comments about this but the one you suggest has no additional power (eg ac adapter) and uses the host power - I presume this would make it mobile but would deplete a laptop battery pretty quickly?