I think Heterogenous computing will play a key roll in increasing battery life in the next few years. AMD, ARM and Samsung among others have been working to get an API together that will allow regular code to work on a CPU or a GPU depending on which will perform the best as long as the processor and GPU are on the same piece of silicon and share the same memory cache. Studies (http://pbbakkum.com/db/) have shown that sqlite gets a 15% performance increase (or less power usage per query) by running the database off a GPU, and Oracle (http://news.softpedia.com/news/AMD-and-Oracle-Team-Up-for-Heterogeneous-Computing-on-Java-295882.shtml) is working on project "Sumatra" which will allow Java applications to get better performance with less power.
Tie this in with Samsung creating a new HSA enabled device, and we could see some interesting changes in the phone market!