Military of hunter's garb might make you stand out a bit.
For this purpose any clothing with a pattern that helps break up your outline would help. A plaid flannel shirt, floral print, or bold stripes for example. "Urban" colors: concrete greys, sooty browns, dull yellows can help you merge into the background.
You're right, I should have qualified my statement to say wear camofalge suitable to the environment. You made some good city camo suggestions. I like grey clothing, it avoids sharp outlines and blends into almost everything in the city. Works day or night (much better than black at night).