The last time I read about backing files up to the iPod, it sucked pretty bad. The iPod won't display RAW files, and it's not made to store files when it's not connected through iTunes. I read it was awfully slow. I think the Belkin Media Reader is the work around device.
See
http://photo.net/canon-eos-digital-camera-forum/00G0bx
http://www.macintouch.com/readerreports/ipod/topic3476.html
http://www.oreillynet.com/pub/a/mac/2003/12/02/photo_ipod.html
for some comments and reviews.
My Giga Vu Pro Evolution plays mp3s (and music videos), but it works better as a photo storage device. This is the opposite of the iPod - which do you want to work better for you? :-> The GVPE is very fast a downloading files from flash cards, shows RAW and .jpgs, and has reasonably good controls on managing your downloaded photos.
My HyperDrive Space doesn't who images, doesn't play mp3s, but it's cheap and works very fast. Many people recommend a Nexto as an inexpensive photo storage device; I haven't owned one, but it gets good word of mouth.
My suggestion is to decide which is your priority: storing photos or playing mp3s. Pick the device that handles your priority best.
If this is a once-in-a-lifetime trip (more or less), I'd suggest at least two different backup devices, because if you have only one, it will fail. The cost may seem high, but compare the cost of redoing the trip if you lose all or some substantial number of your images. I take the GVPE and Space when I'm not going to be able to use a laptop; if I'm taking the laptop, I take an external hard drive and one of the two personal storage devices.
Laptops are a pain because of their size and fragility. I prefer the two PSDs because I can stuff them into my rollaboard between my socks and my t-shirts and they take up little space. But having the laptop in internet cafes with WiFi is very handy for checking email back home, uploading a few photos to flickr, and reading the headlines.
It all depends on your needs and personal preferences. Have fun, and good luck.
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Giga Vu Pro Evolution and Extreme discussion group:
http://groups.google.com/group/gvpe