One of Mark’s recent boingboing posts was on USB flash key memory. I mentioned in the conversation that the Lexar JumpDrive 2.0 Pro seems to give the best bang/buck, being competitively price $80/256MB ($50+ cheaper than an equivalent sized Fuji USB 1.0 drive), and with very fast reads and writes (6MB/s and 4.5MB/s, respectively, vs the Sony USB 2.0 drive that has a decent read speed, but crappy writes (5.5MB/s read, 1MB/s write)).
I had done some research a few months ago for a friend, and one thing that was disappointing to me was the lack of cross-platform disk image encryption. There’s actually a recent Ask Slashdot on the topic. There were some decent posts, including one on why encrypted volumes would be desirable and how it might be possible.
Unfortunately, it seems that there really are no good solutions. Encrypted .DMG seems like it would be a great solution, but it’s OS X only. The only real solutions seem to be using file level encryption, like bcrypt or GPG on a tar file. I suppose one could cobble together binaries and GUIs together to carry around on the key disk?