For iPad launch I brought to Apple Store the first Apple tablet, Newton MessagePad. It was a great device but was released ahead of its time and never gained a significant market share. But nonetheless it was the first touch screen PDA that inspired a whole new category of devices. I have the last version, MessagePad 2100 released in 1997, some 13 years before the iPad. Comparing Newton to both iPhone and iPad I certainly can find some similarities in both software and hardware. Even the names are similar MessagePad and iPad. I think that iPad is in a way a rethought and re-imagined version of Newton.
At Apple Store quite a few employees were surprised to see Newton, one member of the staff even decided to take a photo of it. Take a look at pictures below.