With the number of new devices being announced on an almost daily basis, I'm sure there will be several that produce form factors in a size that appeals to just about everyone.
Though form factor is important to me (I like the sliding screen but prefer clamshell), software is more important. That is why I like the direction of the Mobile Internet Devices (MIDs) and the modified Linux that is to run on them. RedFlag's Midinux should be out any day now, which is what the above device was running as well as Windows. And I'm looking forward to what Ubuntu will bring to the table with their mobile/embedded project.
Who knows, these may even be adapted for the Zaurus and breathe new life into an old but well designed platform.