OK, I'm sure everyone has their opinion on what is and what isn't an important building, but this historical take on the history of buildings in the US is pretty good. It is a little old, so you can have a chuckle at the 80's hair, but the background on why we have skyscrapers is worth watching on that premise alone. I believe it's a UK production, so they are a little rough in their interview process, but that also means that they dig deeper than a traditional 'fluff' piece.
Turn off the reality TV sludge and watch this instead. You might learn something.