Using Emacs as an IDE

I have to recommend Emacs Code Browser as a more "traditional" IDE style environment for emacs.

EDIT: I also now recommend Magit highly over the standard VCS interface in emacs.

You'll have to be specific as to what you mean by "the rest". Except for the object inspector (that I"m aware of), emacs does all the above quite easily:

• editor (obvious)
• compiler - just run M-x compile and enter your compile command. From there on, you can just M-x compile and use the default. Emacs will capture C/C++ compiler errors (works best with GCC) and help you navigate to lines with warnings or errors.
• Debugging - similarly, when you want to debug, type M-x gdb and it will create a gdb buffer with special bindings
• Documentation Lookup - emacs has excellent CScope bindings for code navigation. For other documentation: Emacs also has a manpage reader, and for everything else, there's the web and books.
• version control - there are lots of Emacs bindings for various VCS backends (CVS, SCCS, RCS, SVN, GIT all come to mind)

Edit: I realize my answer about documentation lookup really pertained to code navigation. Here's some more to-the-point info:

• Looking up manpages, info manuals, and Elisp documentation from within emacs
• Looking up Python documentation from within Emacs.

Google searching will no doubt reveal further examples.

As the second link shows, looking up functions (and whatever) in other documentation can be done, even if not supported out of the box.