wl> According to my O'Reilly "HTML: The Definitive
  wl> Guide," --

With all due respect to O'Reilly, the greatest
publisher of technical books on the planet, my
impression of "HTML: The Definitive Guide" is that it
is one of the worst books on the subject I have ever
seen -- badly written, badly organized, with poor
examples, and many things in it that are downright
wrong. I say that having bought it and used it myself
until the pages fell out. Somehow I managed to learn
what I needed to know despite it.

In fairness, I will say that I have what was no doubt
an earlier version of the book, written before the
newer HTML standards came out.

I no longer consult the O'Reilly Guide for anything if
I want to get good information. I use the W3C's HTML
4.01 Specification, which is available from w3.org in
PDF.

As far as using a DOCTYPE string, which has nothing to
do with HTML itself: If you don't care about standards
or how your code is rendered or understood, then by all
means save yourself a line of typing.

If I did not use DOCTYPE strings I wouldn't be able to
use pgml/sgml/xml-mode in XEmacs, which is capable of
doing all sorts of language-specific tricks, including
code parsing, syntax checking, indentation,
fontification, and other nice tricks. Without that I
might as well just get Windows and use Notepad. Except
I'd have to pay money for that, and XEmacs is nuclear
powered and free.

It's been my experience that most computer literate
people find that following standards is by and large
beneficial and advantageous rather than an annoying
inconvenience.

-- 
Lynn David Newton
Phoenix, AZ