Last year we bought the Asus eee901 and took it with us on a short tour. I can say its been very helpfull. I installed some software to help out like Microsoft Map Point Europe 2009, front page, and a few others so I could work on our webpage and upload when I get a chance.
Also worked out well for weather forecasts (when online). We even watched a movie one rainy night
On our 2010 tour we are going to try Skype, (family would like to stay in touch) we'll see how that goes, maybe once a week on our rest day.
We also carry a mobile phone but have let everyone know that we only have it on for a couple of hours a day, say between 7 and 9 at night (in case of emergency).
As for navigation during the day, we just carry paper maps and a compass.