HTML5 (now called HTML)html5.org, smashingmagazine on html5 standard being "living", new shield logo, VERY simple reference to the standard (html5docctor.com), , , , , ,
XHTML 1.0/1.1 , w3c 'xhtml 1.1 basic' standard $free
xhtml should be avoided because it's hard to configure the server to properly serve it up.
html css $free
jQuery, popular $free
you can do effects and animation with this if you are clever.
only if you are going to be a web developer or need access to the innards of the web server or you prefer BASIC to C coding.
XML, optional $free
sooner or later, you are going to run into XML. it is a data format, usually for storing config settings or databases. It is a free-form structure, and it is like HTML, except the tags are custom, whatever you want them to be. you can optionally provide a DTD to define the valid element/tag and attributes structure. only the parser will pay attention to the DTD. Associated technologies you may wish to learn are XPATH, XSLT. oftentimes, XML data might be passed between the server and the browser (AJAX).
search engines, optional $free
dreamweaver, optional $free
tv.adobe.com training videos for Adobe authoring products
make sure you get the right language board. it's a long list and there are duplicates of each board in each language.