The old Stardust Hotel was imploded this morning in Las Vegas. Chief among the structures demolished was the 32-floor main hotel tower.
I mention this because (1) I stayed there twice during The Amazing Meeting (TAM) and was rather fond of the old place, (2) I am sure there are good videos out there, but work does not permit me to find them, (3) A 32-story building is about as close as we'll come to the 50-Story WTC7 or 110-Story WTC1 and 2 for controlled demolition examples.
FWIW, I saw the Stardust in January 2007 when I was in Vegas for TAM5. They were stripping the frontage off of it and you could see the welders' torches both day and night as they prepped the building. It was hardly something that would not be noticed, IMHO.
Funny you should say that, the most sensible analysis that I've read is that the thermite in the WTC served the same purpose, to remove redundant support and prep the building for an instantaneous drop - and then explosive charges did the rest.
You've got to admire it's elegance, in fact you can - a couple of clips from the day caught some of it cooking off just before the collapse, here's one a skeptic prepared earlier ...
http://video.google.co.uk/videoplay?docid=1035128522922802395