I think TDD is best in the situations I enumerated because writing tests for single behaviors of single functions is easy, fast, forces you to discover errors that cause your tests to trivially test, and forces you to discover bugs in your understanding of the problem.

Continuous "Deployment", I guess. The term may have existed before I realize, but it certainly wasn't in popular use before this:

http://timothyfitz.com/2009/02/10/continuous-deployment-at-i...