I recently bought a new USB key as my job commandeered my old 256mb one (I am using it instead of a floppy for the configuration media for the ZoneCD for the hot spot I setup). So I bought a new 512mb SanDisk Micro, and was going to start following some of the suggestions on these various sites and fill the thing up. I plug it in and this stupid U3 service installed and popped up (which is a service far more annoying than useful). Despite deleting the U3 files off the key, they still came back. It was slowing down loading of the key, too, and it was really annoying.
After a Google search, I realized I wasn’t the only one with the problem, and found that U3 has an uninstall application. Apparently there’s a hidden partition that it clears out, which would explain my inability to remove it.
So if anybody ends up with a U3-enabled USB key, there is hope if you value your sanity.