One of the reasons I prefer classic PDAs to smartphones is that it seems nonsensical to spend $700 a year for a data plan just for the privilege of entering my own data. On top of that, for the rss feeds and web sites I track, I feel like a daily sync to the PDA using something like Plucker or iSilo is plenty timely enough. (iSilo in particular is available on a wide range of PDA platforms, even the newer ones like Android and iPhone.) However I am constantly looking for information that will give me confidence that I can use a modern smartphone without a data plan, since I often see smartphones on ebay for a low price because it only works with a wireless carrier with a not-so-great reputation. And I have been without a PDA for a while, I have had two digitizers gone bad (Palm Tungsten T3 and Dell Axim), and I am incompetent at replacing them. This leads me to believe the newer devices must have more reliable digitizers, which makes sense.
I remember when Palm's new Web OS was coming out, there was an emphasis on not making it a door stop when you didn't have a signal. What I am curious about is if anyone has had any success in using a modern smartphone without a data plan, be it Android, iPhone, WebOS, or whatever else is out there. I am primarily interested in PIM functions: tasks, notes, calendar, contacts, not so much email and obviously that is not going to work anyway without a data connection.