I like to use `emacsclient -t` as my $EDITOR (actually I have this in a small wrapper script in ~/bin/editor) so it runs a terminal-based frame rather than opening a new GUI frame. Also, setting alternate editor helps which will just run emacs if an emacs server isn't already running.

I run emacs as a daemon, but it doesn't have to be. You can also run `(server-mode)` from any emacs process. A nice snippet for the init.el is: `(or (server-running-p) (server-mode))` which works whether you run the daemon or not.