x11

Daemon mode is THE preferred way of running emacs (numerous benefits), but the almost certain crash in the event of disconnect from the display is weighing in favour of the Lucid toolkit instead of Gtk.

Note that this happens on local instances also, i.e. you don't have to forward X11 for it to happen. Just start emacs in daemon mode, fire up an emacs frame and close the X server. Emacs will die. This does not happen with lucid, ugly as it is. This is not 'reportedly' more stable, it is a long standing documented buggy behaviour when compiling emacs with the Gtk toolkit.

Elaboration of this situation is in etc/PROBLEMS:

when Emacs is run as a server on a text terminal, and an X frame is created, and the X server for that frame crashes or exits unexpectedly, Emacs must exit to prevent a GTK error that would result in an endless loop.

If you need Emacs to be able to recover from closing displays, compile it with the Lucid toolkit instead of GTK.

Maybe also worth noting is that the Lucid toolkit can be somewhat directly customized via the good old .Xresources. Just edit ~/.Xdefaults, issue an xrdb -merge ~/.Xdefaults, and restart emacs. Gives back some flexibility, lost with Gtk+ themeing. For example, these lines:

will yield this result: