I was surprised how useful my Treo is here in Italy. I've been here for 5 weeks, and it keeps helping.
First of all, being a GSM/GPRS critter, it works here w/ international roaming. If you've tried phones here, its a joy to bypass the hassles and just beam back home w/ no hassle.
But the big surprise was mail. I gave a seminar at University of Bologna and had to communicate with my colleagues. But both apartments I rented had, alas, no phone lines! So what to do? Turns out that Snapper Mail on the Treo is really useful and useable. So I was able to use my standard email using just the phone.
Now this is all pretty tame, I admit, but when you're traveling, its really great to be able to get any help at all. Next stunt will be to use it as a modem for a reasonable cost.