Vim with dwm, TMux/TMuxinator, and urxvt. On the plugin side, I use slimv (I know editing Lisp with Vim is blasphemy, but meh), Easytags, and Syntastic. Just discovered Syntastic: I highly HIGHLY recommend it for everyone ever, just because of how much it shortens the compile-check-fix-compile cycle. Easytags is there basically to make omnicompletion more convenient. Of course, it's all tied together with Pathogen :P.

EDIT: Forgot to mention, I'm primarily editing C, Python, and Common Lisp, but there is some Perl, Haskell, and C++ too.