The kitten on the keyboard of Eur Ing Chris Green resulted in::
I don't want an HTML *validator*, I want an HTML *beautifier* so that it's prettily indented so I can understand it.
Validation, beautifier, spell checker, html version converter, syntax highlighter, image size tag generator, link validator... So it's a big hammer! (Swiss Army Sledge??!)
The usual workflow is load up a document. Tell it what version of html/xhtml to go with. Parse through and fix errors. (It's kinda hard to indent sensibly when there's 5 open table tags, then 3 close ones, and they overlap... Or the table has 11 columns at the top and 7 at the bottom!) Then indent, beautify, convert to whatever. Save. Load into VIM. Break. ;-) And no it's time to stop plugging WindozeWare!
tidy -indent is useful, and I've got it as a vim macro, but can have trouble with some of the more broken html. Haven't tried it in a while, though, has it improved? Also, if you're a TeX user, there's always lgrind (Don't think vgrind has an html mode.)
As an aside, is there an indenter for java anywhere???