Camera Labs

I'm planning a week long camping trip in Scotland this summer, and I will of course be taking my camera. However, I'm going to get through far more than the 12gb total storage I have with my CF cards, so I'm looking for something along the lines of an external hard drive to take with me.
Can anyone recommend something suitable, in the region of around £50? It will need to be battery powered, and be able to save directly from my 50D or CF card. I think 80GB should be plenty.

Any help appreciated

Adam

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Canon 50d, 50mm f/1.8, Sigma 135-400mm APO, Sigma 10-20mm, Lowepro backpack, Velbon tripod, Manfrotto 679 monopod, Hoya filters

www.flickr.com/amr276
Comment and help me learn!

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Nikon D5000 and D300 with 12-24mm, 35mm f1.8, 50mm f1.4, 60mm f2.8 Macro, 18-200mm, 17-55mm f2.8 (all Nikon)