85mm sounds pretty long on a D7000 for street shooting. I would get either the 35mm F/1.8 or the 50mm F/1.8 instead. The 35mm will give you a nice equivelent of just over 50mm, which is a great focal length for this kind of shooting. The 85mm you have will work out at 127mm, which is a good 37mm over your classic portrait length and into voyeuristic telephoto length!