On that subject I would be fine if the browser always rendered in standard mode. or offered a user configuration option to do so.

No need to have the default be compatible with a dead browser.

further thoughts: I just read the mdn quirks page and perhaps I will start shipping Content-Type: application/xhtml+xml as I don't really like putting the doctype in. It is the one screwball tag and requires special casing in my otherwise elegant html output engine.