The second Iron Man 3 clip is here, and even though it doesn't feature any villains, explosions or people wearing armor, it shows how IM3 is going to raise the bar. After Avengers, Tony realizes the entire world depends on Iron Man; no wonder he can't sleep at night (and no wonder he keeps building more suits).
By the way, you may have heard that Gwyneth Paltrow has recently said she doesn't think there'll be an Iron Man 4. This is insanely, completely wrong, as the only thing that will stop a fourth Iron Man movie from being made is the actual end of the world. More likely, Paltrow meant she and RDJ wouldn't appear in IM4, which is possible, but I wouldn't count them out just yet. Something tells me they might change their mind once Marvel unloads multiple dumptrucks full of gold and jewels to their respective Hollywood mansions in 2015 or so. As they say, time and a shit-ton of money heals all wounds.