These pages summarize all the information I was able to find on all presently available portable hard disk-based machines for saving data from compact flash cards in the field. If you would like to see or make comments, please go the the DP Review forum article where these pages were first announced. Thanks!
My priority is still photos, specifically from Canon SLRs. My present body is a 10D, which is easily capable of filling a 1GB flash card (I shoot raw exclusively). So those few devices which write to CDR rather than hard disk are only briefly mentioned; a CDR holds at most 800MB so is not suited to large CF card backup.
There are quite a variety of devices available, many with features which are of decidedly secondary importance, especially when battery life is at a premium (e.g., MP3 and video playing). I've not even bothered to catalog which products support such extras.
In these pages, you can choose from
A more detailed portable storage feature matrix is provided by insidecomputer.com, but it covers fewer devices.
And, just tripped over a site called Outdoor Photos which does what I started out to do here, only a bit better. Lists many devices, prices, attributes, etc. Only thing it doesn't have is the simple summary matrix. [I probably wouldn't have done these pages if I'd found Outdoor Photos sooner.]