You're talking about 200,000 pounds of metal and aviation fuel going at 400-500 mph. Its amazing the buildings survived the initial impact let alone a 1,000+ degree fire which while not hot enough to completely melt the steel is certainly hot enough to severely weaken it. Ever broken a paper clip? Granted that's about as minimalistic as an argument can be made, the point stands that metal doesn't need to be at its melting point to fail.
Now take one of those same planes and slam it into the ground which is already compressed. There ain't exactly gonna be much left of a plane after that...
I assume for the second point you're talking about the Pentagon. That whole thing wreaks of something being covered up, especially with the video footage. You do the logistics in terms of flying with a Jumbo Jet it doesn't wash. What makes more sense is a missile, which, when you consider that is scary as hitting the Pentagon but actually makes more sense then a plane if you look at everything surrounding it.
As for the buildings I believe 7 was built to take an impact like that and if you consider the PLO attacks I refuse to believe they didn't have possible similar precautionary measures for the other buildings. Granted I'm never one to discount human stupidity or arrogance or greed and maybe this was possibly one, two or three but the official explanation doesn't wash for me. I could perfectly well believe three given the greedy, unredeemable fucks a lot of those in the Bush Administration were. Putting out all that bullshit about the Swine Flu to pimp that Tamiflu crap and we know where Rumsfeld was in this. That full body scanner crap that Chertov had a stake in.