I'm curious about this too........ I still have fond memories of my Newton, and would love to use one again.... I'm assuming Newton 2000's and 2100's must be a lot cheaper now.
How useable are they in the "modern world"? i.e. with OS X, modern apps, USB, etc.? I remember the Newton always having a pretty devoted community, but I wasn't sure how long it would have lasted. It would be awesome if there were still people writing new apps for it, etc. The only thing keeping me from getting a Newton really would be worrying that it would just be too difficult to use them now with modern equipment. But if I could still use it for taking notes, working on word processing docs, etc. it would be awesome.