I have adopted emacs as my new editor — a tool with over 20 years of history and polish. It is really more of a virtual Lisp machine that happens to have an editor than it is an editor in the sense of, say, Notepad. It is yet another case of mature technologies that are being adopted by younger developers who gravitate to Lisp-ish languages like Ruby. You know, the ones with bad facial hair who look like they just stepped out of a Phish concert.
I was pleased to see that Marshall Vandegrift has put together a great screencast that shows off emacs for Rails development. It is a thing of beauty, but barely reveals the tip of the iceberg that is emacs. Do yourself a favor and step on up to an extensible editor — one that grows with you.
ANOTHER UPDATE: Thanks to the boys at Reddit, here is a link to the screencaster’s list of tools implemented in that demo, along with another approach to rhtml in emacs. The Ruby-mode for emacs was authored by Matz himself, so there is about as high of an endorsement for emacs as you could get in the Ruby world.