[font color=\'#000000\']There are a number of portable hard drives on the market at this time.
The Digital Wallet is no more. It was replaced by a newer model called the MindStore.
The least expensive PHD would be either the Image Bank (also sold in Europe/Asia as the Image Tank) and the X-Drive.
I believe both of these have the advantage that the user can switch the hard drive. (I know that it's true for the IB - I have one.) That means that you might install a 20 gig hard drive now and replace it with a 100 gig a few years from now when you set off on your year long RTW trip with your new 30 meg camera.
You can choose from other brands that have more features such as firewire, built in viewing screens, LCD status readouts, ability to play MP3s,.... Of course, more features means more cost.
The best source for lots of info on all these units is 'that other' site -
www.dpreview.com - 'Storage and Media' forum.[/font]