Lacie hard drives are pretty snazzy, as are Seagate drives. However, these two makes are perhaps made more for extra storage rather than portability.
For portability and ruggedness, I have a Western Digital external hard drive. It's a 40GB one that spends nearly all of its time in the draw, but I use it to back up pics and music etc. This drive in particular has a purple rubber base which stops it wanting to slide around, and size wise, is not much bigger than one of those Nokia Communicator moble phones.