Chris Harrison and Scott E. Hudson has presented an approach to tackle the lack of tactile elements in touchscreens while preserving its dynamic qualities in their paper: Dynamically Changeable Physical Buttons on a Visual Display.
A bad thing about touchscreens is that you have to focus your visual attention on them when it could needed elsewhere e.g. on the road. Tactile objects, such as buttons, requires less attention, but the user interfaces are restricted by them as they can not be as easily exchanged as elements in touchscreens. Their approach is to combine the good features from them both by “…producing pneumatically actuated, dynamic, physical buttons on a visual display.”.
I think this would be both a fun and useful way to interact with displays as you miss the touchy-feely when interacting with touchscreens at times.
 Chris Harrison , Scott E. Hudson, Providing dynamically changeable physical buttons on a visual display, Proceedings of the 27th international conference on Human factors in computing systems, April 04-09, 2009, Boston, MA, USA
/Gustav Börman, Group H