I've always said that my true desire is a virtual screen - this has to be the limiting factor on mobile devices. We can file our fingertips to use the small keyboards , but using the internet on a mobile device is still not nearly ideal.
I envision the day when we can roll up some sort of large thin keyboard that would then openup and display a virtual screen. Much like the virtual bluetooth keyboard but vice-versa.
This 3M Mini Projector from Samsung might bring this idea closer to reality. Smartphonethoughts has an article on it.