[maker1138]

One of the best ways to increase prosperity for everyone is to make living more efficient/affordable. Look at the average American budget from 2013[0]. The top of the list is housing. Figure out how to make housing cheaper and more resource efficient and you could lower both housing cost and utility cost, potentially saving people hundreds of billions of dollars per year.

Other top items would be transportation and taxes. A $10k safe and energy efficient vehicle would be a great first step.

Though it may be unpopular in some circles, the fact is taxation is one of the least efficient ways of allocating capital. You have administration costs, fraud, waste, and abuse. If we lower the cost of living for everyone, we can lower taxes as well and allow that capital to be invested more efficiently.

[0] http://www.valuepenguin.com/average-household-budget