Even the "configuration files" are, really, Lisp code, not bags of values and options.
Vim configuration is also not a bag of options and values; by default, it uses vimscript. vimscript is an interesting language (supports a form of OOP) but only really usable in the vim world, so it is up to you if you want to learn it to do things besides assign values to options.
Alternatively, vim allows you to do editor customization in perl, and while I have found very little documentation for it, it also supports mzscheme.
How does this kind of thing help anyone? Why is Notepad just not good enough? You can add entire text-manipulation features to your editor, including Intellisense to your specifications, tools for refactoring, integration with other tools outside the editor, and so forth.
Both editors have large communities and have few real competitors for fast and powerful text editing (I hear TextMate comes close).
C: 20% ELisp: 78%
That said, I often trade the time + context switch of moving to the mouse for a slightly less-efficient keyboard command. Overall it's probably a toss-up, I just like to stay near the home row.
My friend at work uses the mouse a lot and he's very good at using it to edit text.
The mouse is better for some things (especially relative/spatial stuff), and the keyboard for others, but interfaces that make you switch back and forth are clearly problematic. Rather than popping up dialog boxes and alerts, Emacs displays results (such as compiler output) in another buffer. If it needs immediate input, it uses the minibuffer, a one-line buffer at the bottom of the screen.
In either case, its full text-editing functionality is available. You can run a directory browser/editor, a web browser, shell, interpreter, e-mail client, irc client, etc., and it's just another text window.
FWIW, Marco Baringer's SLIME screencast ( http://common-lisp.net/project/movies/movies/slime.mov ) is a pretty good example of proficient Emacs usage. That convinced me to try Emacs after using vi for several years.
Also, for you or anyone else reading this thread, http://emacswiki.org/ is the place to go for info.
http://www.emacswiki.org/emacs/TabBarMode
Tabbar works great for switching between the 3 haskell files I have open (note: tabbar only switches between files of the same type).
Regular buffer switching (or even better, anything mode http://www.emacswiki.org/emacs/Anything) works great for switching between the roughly 200 java files I have open right now.
Further, Emacs standard switch-to-buffer command selects the last visited file by default so you can flip between files with C-x b RET. Slightly longer than alt-tab, but not much once it becomes muscle memory.