I agree...learning how to use open source content management systems can save you a lot of time for the kinds of sites that about 90% of people seem to want these days.
Drupal, as mentioned, is pretty good. Joomla / Mambo is another.
Also, Moodle is good for education based sites.
And WordPress is good for blogs, but also with the right template it works well for a lot of other classes of sites (e-zines, band sites, promotional sites, news sites, etc, probably because most of them are really just special cases of blogs).
And of course you have ZenCart and osCommerce for e-commerce sites.
That said, once you learn basic HTML, you might want to decide to refine programming (server side scripting languages such as PHP, Perl, Python, Ruby and / or server side application stacks such as Java, .NET would be good to pick up, as well as JavaScript for client side scripting), and / or design (XHTML, CSS, as well as tools of the trade such as Photoshop, Flash, etc) would be a good idea as well as this will give you the flexibility to be much more creative with your web development.