VERY GOOD PAGE which supports the "normal" collapse scenario

http://www.civil.usyd.edu.au/wtc.shtml

From this page I get this, as some arguments the "Conspiracy Freaks" have come up with:

The fire wasn't hot enough to melt the steel
There has never been a claim that the steel melted in the fire before the buildings collapsed, however the fire would have been very hot. Even though the steel didnt melt, the type of temperatures in the fire would have roughly halved its strength.

There would have been variations in the distribution of the temperature both in place in time. There are photos that show people in the areas opened up by the impact, so it obviously wasnt too hot when those photos were taken, but this is not to say that other parts of the building, further inside were not hotter. In addition, to make a reasonable conclusion from these photos, it would be important to know when they were taken. It might be possible that just after the impact the area wasnt very hot, but as the fire took hold the area got hotter.

The way the building collapsed must have been caused by explosions
One demolition expert on the day of the collapse said it looked like implosion but this is not very strong evidence. Implosion firstly requires a lot of explosives placed in strategic areas all around the building. When and how was this explosive placed in the building without anyone knowing about it. Second, implosion required more than just explosives. Demolition experts spend weeks inside a derelict building planning an event. Many of the beams are cut through by about 90% so that the explosion only has to break a small bit of steel. In this state the building is highly dangerous, and there is no way such a prepared building could still be running day to day like WTC was.

Why did the building fall so quickly?
The buildings did fall quickly - almost (but not exactly) at the same speed as if there was no resistance. Shouldn't the floors below have slowed it down? The huge dynamic loads due to the very large momentum of the upper floors falling were so great that they smashed through the lower floors very quickly. The columns were not designed to carry these huge loads and they provided little resistance.