NASA released more info on the debris strike on the left wing:

NASA admits shuttle launch debris reporting error

More internal emails show concern about launch impact

I still think it looks like a hunk of metal the size of a television impacted the wing, remained mostly intact as it gouged a rut down the underside and passed away behind the shuttle. I think the shower of debris seen coming from under the wing ARE pieces of the wing. The tiles are made of ceramics, and ceramics are good for high temperatures and pressures, but their impact toughness sucks (they're brittle). And I also think the debris came from the solid rocket booster, unless NASA would kindly release a higher quality video showing that it came from the main external tank.

Now I go to sleep. ZZZZZSsssnooore.