Regardless of “the big one” happening I believe health care is a good bet. You’ll be treating the injured in addition to keeping baby boomers alive, they’re the ones with all the money so you know health care is growing for sure. I expect huge medical advances in the next 20 years.
The downside of health care is the potential for increased government regulation and/or socialization of health care. I don’t want to get into a Michael Moore type debate about it but any time the government intervenes it usually means a hit to stock prices initially.