Last year I decided to get back to basics and to dive into using emacs for as many things as possible. It's been extremely difficult and disorienting at times, but it has a non-quantifiable "feels right" quality to it.
I now find myself trying to do as many things as possible in emacs, but emacs + terminal + browser is extremely powerful. I'm not yet to the point of running a shell (elisp shell or otherwise) in emacs, but this troika is very powerful, and I'm extremely happy with it.
That, of course, depends on what you use your computer for, but in my case there are very few programs I don't run inside Emacs: a browser, a pdf and djvu viewer, Mathematica, and a media player. I do use other programs, but mostly run them within Emacs (they're LaTeX, several compilers and interpreters, and a shell).
I now find myself trying to do as many things as possible in emacs, but emacs + terminal + browser is extremely powerful. I'm not yet to the point of running a shell (elisp shell or otherwise) in emacs, but this troika is very powerful, and I'm extremely happy with it.