Read reviews on Seagate (ST9100801U2-RK) 100 Go Disque dur 

Pros: The IPod of external hard drives and not much larger.
Cons: Price and will probably need two USB ports.

This is the fourth external Hard drive I've owned in the last two years and by far the best. Build quality is second to none and I'm a huge fan of this being a self powered drive and not needing any power cables.

Drive comes with a special cable that has two USB plugs; one for power and data, and another for power only in case the drive can't get enough juice from the first connector. I needed both and from the sounds of it that isn't unusual. Mine works with one connector, but with significantly degraded speed. Works perfect with both cables connected, and I have a powered USB hub on my docking station so it isn't a concern. Hey, consider the alternative.