I use at least the first two on the list regularly in emacs; I don't have enum completion setup in C++ code, but it may be available or easily addable with some

I use at least the first two on the list regularly in emacs; I don't have enum completion setup in C++ code, but it may be available or easily addable with some CEDET hacking. The big caveat that configuration is onerous, depending on the target language. I doubt that emacs's IntelliSense-like packages are as good as VS's, certainly in terms of polish and packaging, but what it has is good enough. Also nice is being able to immediately pop up the man page for the symbol under the cursor, as well as language-specific documentation (like the Hyperspec in CL), and the ease of extending it to do exactly what you want, and supporting new languages, can't be beaten. I refuse to work in an environment without jump to definition/references. These things should be considered a bare minimum requirement for a programmer's editor.