Ask HN: What industries are worth specializing in as a developer?

What industries would you recommend to programmers who want to combine domain expertise with software skills? I'm not the best programmer, nor the best domain expert, but I've gotten some great results from combining these two. I've also learned that there are large differences between industries; in how much room and motivation for innovation there is, in how much they value software, how much corruption and politics you'll encounter, and so on.

Are you in an industry where you wish you had more motivated developers? Are there some industries where new or better software would have positive societal impact? Do you have bad experiences from some industries?