Just saw you will NOT be doing PANOS----What do you mean by an "All-round lens"? what will you be using it for??
(edit) No single lens can address all the parameters of making a 360 panorama.
Fewer frames, easier stitching, but lower resolution, go with a full circular fisheye, 4.5mm Sigma 2.8. Better resolution (more pixels) the 8mm sigma will work great on the 1.5 crop sensor of the Nikon.
For even better resolution but at the cost of having to use more frames for a full 360, a longer lens, fisheye or rectilinear will work.
Goto members listed websites to see examples of work. Mine are all done with a Sigma 8mm fishy and Canon 10-22 rectilinear. Really prefer the fishey for ease, the 10-22 for getting more resolution.
PS...any lens will work. You should down-load the trial version of PTgui and experiment before making a final lens choice. More to panos than just a lens choice :-)