They are fading... unfortunately, awfully fast.
I was one of the first adopters - bought a Pilot 5000 from 3Com in a year I don't remember (recall those things?!?). Ever since then, I've upgraded from the 5000 to a III, IIIx, V, Vx, Tungsten T3, and now a T5. Never did buy a LifeDrive or T/X - I think I had hit the limit of functionality - PDA's couldn't do much more that I wanted. Wi-fi needed a larger screen, and the 256Megs or memory or so was plenty.
I looked at the smartphones, but realized the only things I wanted to do with those screens smaller than a PDA was dial numbers. Dunno how people can play games or organize with those things (can you imagine crunching thru a spreadsheet on a BB or cell phone? LOL!). Now, if your job requires you to be on the phone a lot - yea, smartphones/BlackBerry's are very useful. I've tried to relegate checking email when I'm at my desk - I shudder at carrying the Outlook ball-and-weight on the go as much as I dreaded answering calls on the road many years ago.
But in the end, I use the phone for just that - calling people and storing contacts.
I'm right now looking at UMPC's, like the ones from Samsung (the Q1) or TabletKiosk. I need more power than a PDA at this point, a somewhat larger screen, but don't want to go to a laptop. I even still think the 12" laptops are pretty big.
We'll see... it's intriguing that PDA's are going - not sure what's going to pick up the slack.
PM