I've got pretty much one of every main model released by Apple (and some that weren't):
Newton Notepad (pre-release model)
Newton MessagePad OMP
Newton MessagePad 100
Newton MessagePad 110
Newton MessagePad 110 - Clear Developer Unit
Newton MessagePad 120
Newton MessagePad 130
Newton MessagePad 2000
Newton MessagePad 2100
Newton eMate 300
But I did/do have a Nokia GSM interface card for my old Nokia 2110e. Back in it's day it was great to do email and web on the Newton - but rather slow at 9600 baud (mind you the iPhone still isn't much faster.....yet!)
I also played with the Nokia Phonecard 2 back then, but never got it to work on my phone network with the Newton.
I've got a Newton MessagePad 120, 2000 and an eMate 300. All of them were eBay bargains bought within the last couple of years. There is a picture of my 120 and 2000 in my photos section.
Wow! I think macdownunder (a.k.a. J.D.) has us all beat! Here's what I have:
Newton MessagePad 100 x 2
Newton MessagePad 110
Newton MessagePad 120
Newton MessagePad 130
Newton MessagePad 2000
Newton MessagePad 2100
Newton eMate 300
I bought them new when they were released starting with the 120 and ending with the 2100, and I'm still waiting for the Newton MessagePad 2200 or whatever you would call a cross between a MessagPad, an iPhone, and a MacBook.