Notepad++
is the go-to text editor for many Windows users looking for something
better than Notepad. It handles most of the advanced features of the
rest, like syntax highlighting, code folding, and macros, but unlike
most of the other GUI-based text editors featured, Notepad++ is
completely free and open source. It may not be as sexy off-the-bat as
other GUI editors, but it's fully customizable, so you're only limited
by your time and imagination. As for its chops as a text editor, it's
huge following speaks for itself.
Emacs (All Platforms)

Primarily a text editor for serious programmers, Emacs (Editor MACroS)
is popular for its built-in macros and powerful keyboard commands that
make editing text documents—particularly code—a pleasure. The catch:
You're not likely to fully appreciate Emacs until you spend some time
getting to know it. The program has been ported to virtually every
platform and has multiple incarnations, the most popular of which are
probably
GNU Emacs and
XEmacs, both of which are free, cross platform, and open source.
UltraEdit (Windows)

Shareware application
UltraEdit
($49.95) is user-friendly programming editor with support for syntax
highlighting, code folding, macros, and tons of similar features
available to most of the rest. UltraEdit focuses a good deal on web
development platforms, with advanced features built-in for HTML, PHP,
JavaScript, and much more.
TextMate (Mac OS X)

Powerful and attractive,
TextMate
($63) came on the scene just a few years back and quickly gained a
rabid following for its attractive interface, powerful macros, and
downloadable and editable bundles. Windows users who'd love a little
TextMate on their PC should check out
E Text Editor, a text editor that directly apes TextMate and supports TextMate macro bundles.
Vim (All Platforms)

Much like Emacs,
Vim (the child of the age-old
Vi)
is wildly popular for its keyboard macros and powerful set of tools for
the serious programmer. Also like Emacs, Vim is available in several
flavors. Apart from the original, there's
gVim or
gVim Portable for Windows and
MacVim
for the Mac. If you think you might be interested in what Vim has to
offer but you're not ready to dive headfirst into an editor with such
an advanced and sometimes obtuse feature-set, check out
Cream.
TextPad (Windows)

The Windows-only
TextPad
(shareware, $32.50) is much like the rest. It has advanced features for
programmers like syntax highlighting, code blocking, and macros, along
with a clip library feature for storing persistent snippets of text.
TextPad lovers also boast its searching prowess and ease-of-use.
Now that you've seen the best, it's time to vote for your favorite: