The Apple Newton MessagePad 2100 with the Newton Keyboard attached. Perhaps Apple will catch up with themselves one day soon.
I used this set up extensively for some while for email, calendar and to-do items. I carried around an Apple LocalTalk kit as well with a LocalTalk to Ethernet adaptor. It all worked well but the Newton synchronisation software on the Mac was no end of trouble.
The drawing of a weary traveller was done on the MessagePad at the Singapore Airport.