I'll probably do an article on my alternative to PSD for travel - the EeePC (7 inch screen version, running Unix). This cost me under £200, and it has enough solid-state memory to install the Gimp and Ufraw giving raw conversion and Photoshop style editing if needed. It has a good quality webcam, built in Skype, excellent sound recording, three USB 2.0 ports, gigabit Ethernet port, built-in high speed Wifi, and a full Open Source software suite. Best thing is it only weighs 950g with its battery fitted, and the mains adaptor has a 3m long skinny cable and a very neat small plug transformer - great for hotel rooms, where the plug may be badly sited. It also has an SD card slot, currently occupied by an 8GB card which cost under £20.
Although I am still using my Hyperdrive HD80 to download and store CF card contents, this unit is heavy (it includes 4 AA batteries) and need a recharger for the batts, plus a mains adaptor for absolute safety when copying anything like a 4GB card - two 4GB cards copied is enough to drain an entire set of new Duracells. I also have a Jobo GigaVu Pro 40GB, which can view most of my raw files very slowly, but again this needs a mains adaptor and regular recharging. It is very slow copying too. It does allow 100 per cent examination of JPEGs, which the Hyperdrive does not, as that has no screen.
Next trip, I will use a 320GB portable ultra slim USB powered HD - Western Digital Passport, just ordered from eBuyer for £75.99 including postage. I heard about this drive from Pixmania, but their stupidly involved ordering system demanded that (despite being a past customer) I faxed them a copy of my company registration certificate. So I aborted that, and did a search, and found the same drive for £5 less overall from eBuyer without any of Pixmania's potential problems over returns/warranty. I have a small multi-card reader, and the procedure will be to use the EeePC with card reader and Passport drive. It will essential to plug in to do so, the drive will not operate when the EeePC is running on battery power. There is some risk it may not even operate via the mains adaptor and USB, in which case I'll have to carry a powered USB hub/card reader which I have. I'll find that out when it arrives.
Benefits - first of all the EeePC is my link with internet and this website, my email etc when travelling. We used it in Alicante in June, staying in Tryp hotel which offered free broadband access via an Ethernet cable in all rooms. The Tryp brand was basic but at £250 for a city centre room with breakfast, for two, for a full week during Alicante's biggest annual fiesta we found it ideal. If all their hotels have the same plug-in (and wifi) free internet deal, we shall be using them in future. The 7 inch screen is small but just usable. Secondly, the EeePC operating system includes a file browser which not only shows full screen JPEG previews rapidly, but lets you zoom in to 100 per cent on them without opening a photo editing app. It is easy to view and check the copied contents from card to hard drive, which we did on the Hyperdrive. If need be, files can be resized and emailed. I may get a second portable HD (the EeePC plus two 320GB drives still costs less than an Epson P5000 PSD) which could allow backups. I doubt that the power supply will handle two HDs connected at once, it would be necessary to copy the card twice.
I've already found that high capacity SD cards can be surprisingly cheap, and I can easily see the possibility of putting a 16 or 32GB SD into the storage slot and using that to copy over the best edit from cards. Also, USB pen drives are cheap - 16GB of pen drive costs about half as much as 16GB of CF card, same goes for SD. On our last trip four 8GB Sandisk Cruzer pendrives at £15 each would have been enough to back up or store everything.
Anyway, that's my future alternative to PSD storage. The downside is that maybe the solid-state EeePC has more potential to be corrupted or need a reinstallation etc, than a simple dedicated storage device, and the portable HD plus other memory devices can't back up from a CF card on its own. This is where a future product - a USB pendrive with firmware able to access USB Mass Storage Device protocol and copy files direct from the camera - would be a great asset. Even better would be file upload menus on the camera's own screen to copy to such a simple external solid state image store.