The main large project you're likely to use that does not really play well with TypeScript yet is create-react-app. There's a TypeScript fork [1] which works reasonably well, but "reasonable" is not really what you'd hope.
That said, the strong community push means that they're at least considering it. [2]
[1] https://github.com/wmonk/create-react-app-typescript [2] https://github.com/facebook/create-react-app/pull/2815