Mark, the tablet team agrees with you.  One of the things we learned with V1 was that the enhanced mobility enabled by Tablet PC exposes a lot of work we need to do to make power management better.  Laptops are used mostly as station to station desktops, rather than as truly mobile devices like PDAs and SmartPhones.  Of course, this is not uniformly true, but if you observe a significant number of laptop users you will find this to be the norm.  As tablet started to push in thedirection of increased mobility we became increasingly frustrated with the limits of power management in today's HW and SW.  Hence the new name of our division, Mobile Platforms Division.  As we described at a high level at WinHEC, we are focusing on power management improvements as key enablers for tablet and mobile PCs in the Longhorn release.  There are defined physical limits wrt today's batteries and transistors.  While technologies like fuel cells look promising, they are not yet ready for prime time in a portable computing device.  Until we are able to “cheat” the laws of physics we have to get smarter about how we manage the power budget within the parameter space defined by current technology.  Better power management capability enables users to configure and use power management features like display dim or off, S3, S4, etc so that the effective battery life is much improved, and not at the expense of device availability.  Ambient light sensors connected to a display brightness control are an example of improved HW/SW power management.  There are many others.

One tablet user tip I learned from Chuck Thacker, the designer of the original MS tablet PC prototype:  Whenever I set up a new tablet I immediately reconfigure one of the buttons to control screen off.  I don't use buttons for launching Journal or TIP, esp with the in place TIP in Lonestar, so I am always ready to sacrifice those button actions.  When I am using my tablet in a meeting or at home on the couch I just activate the button whenever I pause to think or actually engage in conversation with another human, possibly even a family member (yes, it does happen from time to time). A tap of the pen on the screen turns the display back on.  In Chuck's prototype the screen was 4 watts out of a nominal 10 watt power budget so just this simple discipline greatly extended the battery life.  It's almost half way to S3 without any resume issues or delays. The savings might not be quite as dramatic with other tablets but still significant.