Having used Palm, Blackberry, Sharp, Psion, Sony Clie, Symbian v6 thru v9 (both Nokia and SE), Outlook etc etc, I can honestly say there is only one winner. I cannot see it ever being beaten.

Of course, I agree with previous posters, it is the Psion Agenda. Simple, effective, reliable. I've owned most Psions from the 3 through to the netBook, and they were all brilliant, and sadly demised before their time. It's is doubly ironic that the most popular range of laptops are now called "netbooks". They are a pale shadow of the true original, with 10+ hour battery life, true instant on-instant off, etc.

I have to say though, the N900 is the closest thing I have found as a proper replacement!