What's the oldest mobile device left in your house? I think mine must be the Psion 3.
Psion 5 Mx with a 4 Mb memory card.
Somewhere in a box there is my first mobile phone. I know it's a Nokia, no idea what model it is, only that it was the first mobile phone available from Telstra. I still have my first Palm too (US Robotics Palm Pilot Professional).
Most things that old are long thrown out or sold, I do still have a Sony Clie SJ22... No way to charge it up though, lol...
Either ipod touch 2g or fujitsu Siemens loox n560.
I kept my first mobile device, my Palm IIIc, for sentimental reasons, and to give me a concrete example of how far things have come in such a short time.
Device? got a couple of old nokia's floating around - not sure if they even work.
The oldest working device we having in our house at the moment is either a very old Sony DVD player (can play flat or upright - cost a fortune but is now around 10 years old - never been repaired, cleaned or maintained - doesn't like to play dirty discs but other than that works well) or a very old B&O wall mounted CD player..(with the door that opens up automatically - not sure how old it is but inclues a radio and a cassette player).
After reading Jaam Gans response, my thoughts went to my oldest non-mobile device which would have to be my alarm clock; a GE Programmable Dual Alarm Clock Radio which has been running every day since sometime in 1986. Despite searches, I have never found a suitable unit to replace it should it eventually fail or require retiring.
Hmm. No small devices are old. My iPhone 4S is 8 months old and my Galaxy Player I've only had for a couple of months. But since I consider a laptop to be mobile tech, that honor goes to my MacBook. It's 6 years old and still in use by my wife and other than the swollen battery, which I'm not going to bother to replace, it works just fine. (It's always plugged in and used in desktop mode anyway).
Original Newton MessagePad.