Always loved the smallest of the small laptop PCs, but seems they never really took off for a number of reasons -- form factor is limited by keyboard size (chiclets anyone), features tend to not be pushing the envelope and price is high (smaller means pricier -- MacBook Air anyone).
Now Acer and Dell seem to both be getting into the act. Read more about Acer's latest offering (with photos) here on the UMPC Portal.
Ah, if we could only carry one gadget that could do it all ... will it be phone, computer or wrist radio (Dick Tracy, anyone) ...
That's one of my favorites pictured above -- Compaq's Contura Aero -- note the trackball location (thanks to the Home Computer Museum)!