Very true.  Intel has actually been very in-efficient over the years, and has recently come up with some good research to fight back so they can have a place in the tablet/phone market. In other words, mobility has created a high demand for efficiency that will likely yield to improvement for years to come. 

Also, it's worth noting that if you live in a cold climate, computers can be used to help heat the home.    That's what my i7s do.