vi and Emacs are two powerful editors that many hard-core or experienced
UNIX developers use.
Their keyboard conventions and user-interface are not compatible with those
of more recent Windows-like editors (or with each other), and they both require
some time getting used to.
Thus, it is recommended that people who have a lot of Windows experience not
use them right-away.
Of the various vi clones, the most powerful, popular and recommended is
Vim which has a GUI version titled "gvim".
There are two popular and currently maintained versions of
Emacs: GNU Emacs
and XEmacs.
They are all also available for Windows and for other non-UNIX platforms.