Cnet has put up an interesting article talking about Intel's progress and research into developing ultra-low power microprocessors. We aren't talking about just die reduction, though. About half the power consumed by a high-clockspeed processor is leakage, power that essentially is completely wasted. It isn't providing anything to the CPU, it is just being dissipated by heat - and straining the battery of the machine should it be a mobile.
With their latest core revisions, Intel has introduced modifications to their core that will prevent a large portion of leakage current. Thus, though you may be getting only a minimal reduction in the amount of power used for useful purposes, the gross power draw is significantly reduced. If you recall from the IDF, Intel laid out a roadmap that had 65nm and even 40nm mobile CPUs consuming less than 5W. The smaller you go, the harder it is to prevent leakage - this is something that effects all microprocessors. Although this isn't tackling the issues of continued problems in reducing size, it's a way to make huge improvements in TDP of all processors. 12-Hour-Battery laptops may become quite real in the near future.