Integrated Development Environments

Eclipse - Powerful IDE written in JAVA.
Free Pascal supports both a text-mode
IDE and Lazarus (see below)
jEdit - Editor written in JAVA which can be
expanded to a full IDE with plug-ins.
KDevelop - Standard IDE for KDE.
Lazarus, a cross-platform IDE for Free Pascal,
a 32bit / 64bit professional ObjectPascal compiler.
Emacs - Powerful IDE,
extensible in LISP, ships with modes to integrates with SCM (GIT,
SVN, CVS…), build systems, debugger and even fancy multi-window
with ECB.
VIm - Powerful IDE, extensible with
scripting, can use various modules for completion and more.
KScope - Cscope based source
editing environment with KDE.
Anjuta - IDE with nice plugin support
QtCreator is an
nice IDE which has code completion, remote deployment (with version
2.3) and Outline view. It also has an VIm mode. Its menus are much
cleaner than these from Eclipse and its easier to get started with
this ide than Eclipse for that very reason.
Embest IDE for ARM