Wind, definitely. Forget moving stuff around (which is awesome), do you know how destructive air is if it stops or stands still? suffocation at best and implosion/explosion at it's most fun. Let's put it this way, the Earth is spinning at a few thousand kilometers per second. What were to happen if your relative space was suddenly held in absolute position? You would instantly be decelerated and relatively accelerated to that speed. If you survive the initial deceleration (which is like hitting a smooth pool of water at, well, a few thousand kilometers per second), anything you hit at that velocity would liquefy you.
Now for some non-lethal stuff. 14psi may not sound like much, but it makes one hell of a strong prison, and is impossible to break out of, because there's nothing there to break. Wind can deflect everything, even lightning (it's got to travel through something, doesn't it?). Wind/air can also simulate most if not all of the other elements. Air can easily create or summon lightning. Air can be compressed to generate heat and fiery blasts. A well-placed gust can summon a rainstorm or tidal wave, or blizzard or hail storm. Air can vibrate to crumble rock and earth and even steel, and kick up wicked sandstorms and rock slides.
For my second choice, I'd probably choose Ice. (pfft, ice and water overpowered? ha!) Ice is one of the fastest-acting elements (believe it or not) and has nearly as many applications as Air/Wind does, some in the same ways. I especially look forward to instantly chilling an area to absolute zero, simultaneously shearing off whatever was inside it and crushing it when the created vacuum gets filled in by the surrounding air.
...I swear I'm not evil.
So unless you make friends with your elemental enemies, sorry, but no metal for you.
