You know what, it's hard to argue with some of the stuff in this (spoilery) Iron Man 3 video from How It Should Have Ended. Specifically, how it calls out the movie's biggest WTF moment.
I liked the movie a good deal, but I had the same question at the end: Why on Earth did Tony blow up his suits? I get the gesture, and it's sweet and everything, but dude… you're probably going to need a suit at some point. Maybe even soon! Evil can be somewhat unpredictable, after all.