Are you talking about civilian wear in Iraq/Afghanistan as a civilian? Or, are you talking about civilian wear as a soldier?
If you are going as a civilian, and wearing civilian clothes, buy high quality, tough clothing, not cheap crap. You don't want your attire to fall apart on you.
If you want cargo-type pants, look at the 5.11 tactical pants. They last. I like the new rip-stop, it's lighter and cooler. Don't get the nylon. The heavier canvas is ok, just hotter.