If I buy the AFS 18-55 VR would it be like a necessary upgrade to go to AFS 16-85 DX VR to better match the D7000 ? Is the 16-85 a more versatile lens like for portraits? If an upgrade should be expected, would it not be better to invest $ 659.00 now instead $ 199.00 and then the $ 659.00 ? Considering the lens I have now, AFS DX VR 55-200 F 4-5.6 and AFS DX 35 f1.8G would the 18-55 be the most useful complement? Please feel free to suggest within the alternatives now being considered and out of them also.