We have discussed this issue before:
https://www.pentaxforums.com/forums/pentax-camera-accessories/14643-photo-hard-drives.html https://www.pentaxforums.com/forums/general-talk/13305-portable-hard-drive-would-you-choose.html https://www.pentaxforums.com/forums/pentax-dslr-discussion/11871-transfering-...rd-drivre.html https://www.pentaxforums.com/forums/pentax-camera-accessories/10733-photobank...ggestions.html
That said - I use a Wolverine flashpac 7000 portable 40GB hard drive.
External Hard Drives I have carried it all over - including a month long trip to New Zealand. I bought it in 2005 - simply because I wanted a way to travel around - without having - to carry a laptop.
I am fully aware that if I drop it, step on it, spill coffee on it - it will die - but so will my camera. It is pretty well protected and all it does is read multiple memory card types. It also can/will fail sometime due to --- well hard drives just fail. I am not paranoid enough to think that everything is just going to die. If you are afraid to carry a portable hard drive - just because you think you might drop it - how about a laptop, ever dropped one of those?
Other things to consider - electrical outlets and power coverters. I bought the Wolverine car charger (it has a L-ion battery) so as long as I could get to a car, I was fine. I also had my solar cell charger too - has a cigarette outlet on it - that I used to charge the Wolverine (too see if it would work) and power my year 2000 class PDA and GPS combo. Most of the time I just used my power converter to charge the battery.
During the trip - I carried all of my cards at the time (about 10GB) but only transfered the data to the Wolverine in the evening. The Wolverine stayed in the appartment/hotel while I was out and about. Between my son and I - we shot 21GB of images (this was not a pure photo trip - it was my wife's vacation too ya know). My workflow is this.
1. Take a new SD card out of the SD card storage slot in the carry around camera bag.
2. Put the SD card into the camera and format the SD card.
3. When the SD card is full - take it out and lock the SD card.
4. Go back to step 1.
Back at the appartment/hotel
1. Take out all SD cards that are locked.
2. Insert locked card into Wolverine and copy images.
3. After copy has completed - The Wolverine will turn it self off - or you can just watch - boring.
4. Remove card, un-lock it and put it back into the bag.
Single point of failure - yup - but for a while there I thought I lost my 4GB card in NZ too - before I got it copied (in the couch behind the cushion). Could it be stolen - yup - but not as enticing as a laptop or DVD burner. Slow - yup - but there was little else to do. Could not see my images (my model does not show you the images) - yup - but when shooting film for 40+ years - I could not see the images either.
I now have 25GB of SD cards - maybe the next time I go out and about for a long period of time the Wolverine will stay home. But I really doubt it.
The Elitist - formerly known as PDL