in reply to SGML FAQ to HTML (or XML? or SQL?)
Since you aren't actually using any SGML syntax that is not part of XML, I would recommend using XML, since the tool landscape is currently much more full for XML than SGML. Using XSLT, I would probably combine it with mod_xslt which translates XML to whatever, on the fly. It also has caching capabilities. For the generation of HTML output, using the latest version of the Docbook XSLT stylesheets should be fine.