No body cares about your pants, generally. Camo in town will get you noticed, built in plastic knee reinforcments, or shit bristling from every pocket will too, atleast by me. If you wear cargoes/bdu style solid color pants you will not stand out, especially in a brown or grey, unless of course you add "combat" boots/hikers, tuck your dark colored fitted or leo/mil/gun tee or polo, showing your tactical/rigger belt, leatherman and/or surefire and wear your wrap around shades inside.
If I need extra pockets, mobility, or quick drying I wear LAPG's classic BDU pant in coyote cause they're cheap, or Columbia's of some sort that I found on sale. Carharts are nice, but hot, take forever to break in, and days to dry, the material also abraides itself, absorbs everything, stains easily, and burns pretty readily, I don't mind character, some might, for me their mobility sucks, combined with the abrasion factor the crotches always fail long before any other part is ready to go.