For serious input, I'd have it lying flat or slightly inclined.  For meetings, I'd have it on a stand on the tabletop. For Augmented Reality, I'd be holding it out in front of me, possibly with both hands.<p>This post was made with a Windows tablet, BTW, as have all my posts for a  week.  My tc1100 works best lying flat for serious input.  I suspect that will also be true for a non-stylus interface.