Gotcha. Well, a few themes I don't see often are apocalyptic, city, and stand-alone movie themed towns. Those can be super fun to create.
Another theme I don't see too often is a politically centered town. My first town in New Leaf was a communist dictatorship. I even wrote a manifesto for it. Then again, towns like that aren't normally people's first thought when playing AC.
But obviously do whatever you feel is best!