All good replies, thanks everyone. A USB drive, although very useful, isn't really what I'm looking for, seeing as if my bags get stolen, I've lost everything. The Gmail idea is OK, but as far as I know, there is a 10mb attachment limit (the shell extension just e-mails your files) and accessing the files again from, say, an internet cafe might be tricky, assuming they don't have the shell extension installed.
I'm also thinking it must be possible to access files using my PalmPilot, with WiFile Pro or similar... I have done this across a LAN, but over a WAN might be more tricky. Again, keeping the data remote incase someone nicks the PDA. That said, I could always just e-mail important documents to myself, although last time I looked, I had no encryption software on the Palm.