Finally after nearly 21 months of good and trusty service (never once losing a bit or power) my Sony Clie T425 was euthenased tonight. I'm moving to the much more capable and far quicker HP h4150, though navigation will be done by the Palm Vx as it is the only device capable of accepting a GPS that I have at present.

The T425 is a little publicised unit which had a very good battery life - something in the order of tens of days with heavy use, and possibly months on standby. If I recall correctly, the lowest the battery ever got was about 60 % charge after two weeks away from a mains point.