I use two devices and let me say that I was and may still be adverse to smartphones, though I have and use a Treo 650 now and have found a few redeaming qualities about using this ALONG with my NX70.
I use the Treo as...well...a PHONE, go figure
But I also found out that the alarms are a LOT louder then any PDA I had before, so I keep my Agendus on there. I have used Agendus since the early Action Names days for keeping me on schedule with my appt's and "to do's", so the fact that I could hear the alarm from 1 level away in my house (like I'd ever leave my PDA that far away anyway!!!) made it a great tool, that I soon found I couldn't do without as the whole reason I bought my first PDA was to replace my DayTimer and be more portable and have alarms so I would not be stuck out and about without my schedule, contacts and such.
So to make a long story short as I won't type out the multitude of ways I use my PDA's today, I will simply say....
I use the Treo for things that I HAVE to have with me all the time and can tolerate the smaller screen for, such as Agendus, BugMe, Woman, Fuel Log, etc.....
I use my NX70 for things that if I go to the store for 20 mins, I can live without such as games and ebooks, also for things that I can't tolerate on the smaller screen such as ebooks, Bonsai, DayNotez, Word to Go, Tiny Sheet and many others.
I do find myself carrying 2 PDA's often which is my major grip with smartphones, I can do without a phone but not without my PDA! But for now, this works for me and I do like the ability to text on the phone anywhere I want
Btw, the phone was a gift, I wouldn't have bought a smartphone for myself, I would have bought a new PDA and kept my cheapo phone