Spending some quality time researching and thinking about what you want to speak about is a pretty great idea. It's an important decision on your "Platform Journey". I actually keep an on-going list of ideas (and I'm not even a competitor). You should too! With phones that take notes and access to computers, jotting down a few ideas that you can explore when your ready to dive in, is pretty easy. This list doesn't start when the speech season starts... It's on-going.
There are so many fascinating subjects, people, events, etc. I honestly don't know if I was competing, if I would ever be able to choose?