Seagate GoFlex 250 Gb Portable drive.
I picked one of these up last week for use as a backup drive for my Powerbook. I connected it to the home network through my office based Airport Extreme.
Set up was easy and once formatted for Mac via Disk Utility, the drive was up and running in minutes.
I really like the sleek design of the drive and the inclusion of an easily interchanged connection. It comes with a USB connector that connects into a ‘bracket’, which then connects to the rear of the drive. Other connectors, should you want them are Firewire 800, eSATA or even USB 3 - so lots of room for future-proofing!
Full details can be found here.
In short, if you are looking for a fantastic and relatively cheap portable drive, this could well be worth a shot!