Meh. There's a difference between "validating" and "valid", IMO. If I know my site is valid, then whether it validates is really no biggie to me.
Of course, my site is not valid for a couple of different reasons (micro-id's can't validate yet), but my point is that the goal should be to make the site as valid as possible given the specific limitations and desired features, not to shoot for 100% validation all the time.
Just my 2 cents. :)
