Not really familiar with TurboGears, but it's always awesome to see an app leveraging a language's natural power and flexibility.
I concur about decorators being "insanely easy to use"--taking the memoization example I presented in the article; it's far, far simpler to tack on "@memoize" than to incorporate it into the flow of a function and risk losing clarity. I am sure TurboGears (and Django/Pylons) authors love that you can decorate something with @login_required (or equivalent) and have that method exposed to authentication.
They are very useful and insanely easy to use in python.