Tamron SP AF 17-50mm ƒ/2.8 XR Di-II VC LD Aspherical (IF). This is the reduced-sensor version of the Tamron-built lens I've been using for the past four or five years, most recently for these shots.
B&H has announced instant rebates of up to $150 on select Tamron lenses, good through the end of the year.
Featured Comment by Sam: "The 17–50 ƒ/2.8 VC in Nikon mount is probably my most used lens these days. A great bargain for under $700 and much more useful for me (thanks to stabilization) than the far pricier Nikon 17–55mm ƒ/2.8."