i never understood the point of mimicing the eyes adjustment to light changes in the game. You are viewing the game through your eyes. They ALREADY have this effect. The game just ends up doubling the effect pointlessly.
Ehm, no. The eyes (and brain) can handle real life brightness values. But a monitor cannot, at least not cheap household monitors. The eyes (and a camera for that matter) control light gathering by opening or closing an aperture. That's what we see happen in game. Want to buy a HDR capable monitor? Check this out:
http://www.mobypicture.com/user/CineBill/view/7473526
Hope you can afford forking up $55.000 for it though

So far we're getting real time application of auto exposure, similar to what a camera does. Maybe some day we may get real time local adaption, but I'm expecting more problems with that than with auto exposure showing a limited range and clamping the rest. Remember how awful bad HDR looked? Examples:
http://images.google.com/images?um=1&hl=en&safe=off&client=opera&rls=en&biw=1095&bih=867&site=images&tbm=isch&sa=1&q=bad+hdr&oq=bad+hdr&aq=f&aqi=g10&aql=&gs_sm=e&gs_upl=15210l15613l0l15738l3l3l0l0l0l0l270l270l2-1l1l0