The greybeards all say "unix is an ide". I think I first heard that from Tom Christiansen when he was heavily involved in the Perl community back in the mid '90s. Even today, some of the most productive programmers I know only use X/Gnome/KDE(/OSX) as a means of organising terminals on modern hardware.
Acme has that neat feature of interpreting text as potential hypertext -- each of several addressing formats [3], when clicked, opens indicated file or resource, at the indicated point. Click on compiler error message and you get there. Prepare a command, click on it and you execute it. Etc., etc.
Also, unlike the mainstream IDEs and editors, those two work surprisingly well over network.
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[1] http://en.wikipedia.org/wiki/Sam_(text_editor)
[2] http://en.wikipedia.org/wiki/Acme_(text_editor)
[3] implemented via http://en.wikipedia.org/wiki/Plumber_(program)