In pictures of Iron Man 3 we see Tony has a room with what I am guessing are old armors. What are they all?
Here are two other angles:
They are all the past models of Iron Man armor, or at least placeholders for them. At the end of Iron Man 2, it's implied that Rhodey kept the War Machine armor, which was the Mark II, and yet there's an armor that looks like the Mark II in that lineup. From left to right, they are:
the Extremis story arc featured Tony building a new suit of armor that could be mentally remote controlled by Tony. The armor moves via additional repulsors on each piece of armor, which allows Tony to fly the pieces of armor onto himself. The Extremis storyline has this made possible by Tony becoming a cyborg, but the trailer doesn't make it clear if this aspect will be part of Iron Man 3.
They are the Iron Man armors in technological progress from the Mark I to the Mark VII.
Iron Man Armor Mark I - far left
through Iron Man Armor Mark VII - far right
Mark VIII is the newest golden armor in the center panel.
The Iron Man Armor is arguably one of the most powerful forms of technology developed by Tony Stark.
Alone, the Mark I was sufficient enough to allow him to go through armed terrorists in order to escape.
The Mark II was sufficiently powerful enough to go toe to toe with a more advanced and updated version of the armor (the Mark IV).
The Mark III was able to battle the Iron Monger suit, however, with some difficulty (due to the fact that it was powered by the first generation mini-arc reactor and the Iron Monger was powered by the second arc reactor he made upon his return).
The Mark V, while lacking weaponry and flight capabilities, was still able to take on Vanko while just utlizing just the Whiplash harness.
The Marks VI and VII proved to be the most powerful generation suits used by Stark. They were powerful enough to battle hordes of Hammer drones, Vanko with his own armor, survive and battle two Asgardian gods (Thor and Loki, respectively) and hordes of alien foot soldiers and large transports (the Levithan).