Three Things Supporters of the Official WTC Collapse Theory Don't Like to Talk About
2) there WAS fireproofing on structural steel, thus ordinary fires should not have weakened the structure significantly (the NIST idea that the "plane crashes" stripped insulation from a large proportion of the structural steel is unsupported by evidence and is extremely improbable).
3) the odd fact that for BOTH towers, initial asymmetric damage turned into a symmetric global "collapse"
4) the fact that despite very different damage and fire patterns, BOTH towers were completely ablated, down to their bases, and both towers showed a similar violent mechanism of destruction
5) the NIST model of "collapses", where part of one floor collapsing pulls apart the core then pulls down the whole tower, is completely illogical and filled with flaws
There is also the other evidence that people point to as evidence of demolition, but usually official story supporters have some form of rebuttal for this evidence.
I have not seen good rebuttals to these points above, however.
UPDATE: Clearly, NIST simply cannot explain what happened to the towers. There is SO much to criticize in this letter, hopefully I will have a chance to post a more extensive critique of the NIST letter in the near future.