But that's the beauty of Windows tablets and why I think Windows 8 will do well. They can be used in a number of different ways and in a number of different environments. You won't need a tablet AND a PC, one device can serve both purposes and be a main computer without giving up much. Currently with the EP121 you do sacrifice the long battery life of the iPad but hopefully Windows 8 and new Intel chips will improve upon that.
Maybe I'll be wrong but I just simply don't ever see this day coming. Maybe tablets will be able to serve as a main computer for some people but unless they can do the exact same tasks at the exact same speeds that the PC can, a tablet will never replace my desktop.