This is where some sort of iOS “guest mode” would be neat, to be able to sign into your iTunes account for a few minutes, download your favorite app or two, maybe a TV show from your iCloud library, access your email, and then sign out when you’re done and wipe your data off the device. This would also be useful when you’re visiting friends or relatives and want to access your stuff from their iPad.
In general, iOS doesn’t seem to be set up very well for sharing, and if the iPad is going to become a public-use device, it would be nice if Apple improved that experience. But for now, it’s better than nothing, I suppose.
This is high up on my wish list too, but in a slightly different vein. I just would like to be able to let someone else use my iPad without them being able to access my email and other stored data. A guest mode: yes — just perhaps one that allowed someone to use just Safari and apps that I designate, where everything else remains walled off. That’d be pretty useful.