Yeah I won't be selling my old iPhone either. I'll either keep it as a backup or just give it to a close friend or family member. That would be rather unfortunate to have all of your information that you thought private exposed.
I was thinking that as well. Use the new iPhone as the App Store downloading machine and take advantage of what Apple has to offer and use the current iPhone for those applications that haven't made it into the app store yet.
My 3 year old nephew actually asked today for an iPhone after he played with mine. He's not that bad of a photographer with it.