Old AI is today's bleeding edge computer engineering. There is an enourmous amount of free lunches for computer engineers and software startups in the old school artificial intelligence.
* modern SAT solver performance is impressive. They can solve huge problems.
* Writing a complex systems configurator with Prolog or Datalog can be like magic.
* Expert systems. There has never been so much use for them than today. Whenever you see expensive systems utilizing complex mess of "business logic" and expensive consultants, you should know there is a better way.
(I use SAT-solvers to partially initialize neural network parameters).