I always think of Emacs (never used it tho) as a Smalltalk system without images and with Lisp instead of Smalltalk as the underlying language.
Every visible and invisible think is inspectable and changable at runtime, yup - pretty cool and I loved it for programming! Not sure whether I want to get on the emacs train tho. I have problems mantaining efficiency either way already... And I favor tools that work without set-up. Then again I am still young enough that learning investments pay off by a huge margin... tough.