I'm steadily getting to grips with the D300 and currently tend to favour using the Tamron 17-50mm over my 18-200VR, although at a wedding last weekend I used the 18-70 mainly due to better low light focusing. At the wedding I also borrowed a Sigma 70-200 f2.8 for candids etc. The Sigma showed good image quality and enabled some nice depth of field control, but the focusing was twitchy and lack of VR was a pain for hand-held shooting (using a tripod was impractical at the venues). My budget means that I can afford either f2.8 max aperture or VR but not both. My 18-200VR does not cut it at longer focal lengths. Therefore, there are two possible candidates: either a new 70-300VR or a used 80-200 (two ring version due to faster focusing). The lens would be used for candids, some landscape / architecture / portraits etc. The attached image shows what I'd like to be able to achieve on a more consistent basis. Any advice from present / former users of both lenses would be welcome. Image below taken on D80, Sigma 70-200 @ 200mm, 1/60th hand held, F4, SB-600, ISO 1250.