I use HTML 4, not XHTML. I think a tag without closing tag can be denoted with <.../>, that way you don't have to close 'em. Best way to put a common header and footer on everything is a script. Batch is powerful enough (use piping!) for that.
Is <style="blah"> even a valid tag? My website uses a batch script to assemble the headers, footer and page content and it validates before I upload it, after that the host completely butchers the HTML with their ad code that causes roughly fifty validation errors. I've just written a new batchfile: @echo off echo…