IRON MAN the second time around was interesting. I noticed something...
Anybody else notice that all the bad guys in the movie have big-ass rings?
No, not just the terrorists; they're the Ten Rings, after all, and they're widely theorized to be the subordinates of the Mandarin, who would be awesome and thoroughly logical to be the villain in the sequel. (My pick for part III's baddie, incidentally, is Fin Fang Foom; an IRON MAN trilogy would work great with E.E. Smithian, LENSMAN-style villains -- i.e., the sort of big bad whose menace is incalculable until they're eradicated, at which point it turns out that they were merely a front for an even *bigger* bad whose menace is TWICE as incalculable as the previous lot, and so forth.) As everybody noticed, the terrorist baddies both wear big-ass rings and fiddle with them prominently, the better to draw our attention to them. What I didn't notice until the second viewing is that Obadiah Stane wears a big-ass ring, too; you can see it well in the scene where he has Tony paralyzed.
As liviapenn and others have noted, the big hole in the movie is that there is no earthly reason for Stane to kill Tony Stark; certainly not to kill him when he does. If, however, he's working for the Mandarin, then maybe there's an explanation. The Mandarin could have ordered him to do it. As to why, or why the Mandarin would play one hand against the other, you got me.
Okay, further fanwanking: maybe the whole thing was the Mandarin's idea. He ordered Stane to put a hit on Tony, knowing Stane would farm the work out, with the best candidates, given circumstances, being the Mandarin's own guys. To whom the Mandarin gave his own orders, all the while expecting to sacrifice their lives, on the theory that Tony Stark, with his life at stake, would come up with *something* to escape. Something brilliant. Something that the Mandarin might find useful.
Okay, it doesn't make real-world sense, but it makes decent comic book sense, doesn't it? In a way.