Perhaps you can look at optimization or machine learning. Optimization of processes and algorithms can be applied to almost anything out there and Obviously machine learning is new and hot and will continue to be a hot topic in the near future.
Also, what do you think of iOS development in terms of entrepreneurial ventures?
In terms of iOS and entrepreneurial ventures my opinion is that you shouldn't focus on say "iOS" as you have framed it. Startups is about finding a problem and building a product that people will use. iOS is a tool that will help you to do so. Likewise the product could be a website (so you'd use a different tool to build, such as ruby on rails) so it ultimately comes down to what you want to do. If you don't have a technical background, even to do a business role in the tech world, it won't hurt to learn one programming language as from there you will have your foot in the door.