One of these....
In me wallet, with a slightly hacked knoppix linux boot cd image on it.
Means I can boot any modern PC (new enough to boot from USB) into a pretty usable and rather slick Linux. It does full hardware detection and support, essentially doing the same job as a 1hr windows install (with better results) in about 40seconds each boot
although it obviously does not support bizarre or non-standard devices, and cannot provide 3d acceleration support on Nvidia and ATI cards because knoppix cannot legally distribute the drivers.
Mind you, I have a 300mb writable /home partition on there as well, I could easily add drivers, but I'll probable stuff it with extra programs and media codecs (again, not legally distributable) to get full avi and dvd-menu support.
I'm just SO chuffed with it, and even more chuffed witht the looks on ppl's faces when they see their machine boot from something the size of 2 phone sims and run better and faster than they ever seen it (and that is even WITH the slow speed of flash memory).
You could also, as I plan to do, stuff a 2GB one with NO vids and mp3's,a true portable media library you can use on any machine without having to interface to an ipod or anything.
