Nikon 17-55mm

If you can live with the gap created at the longer end, this lens is superior in every way - and I wish I had it  

 

I replaced the 18-70 with that lens. It's fabulous. Not too bad wide open at 2.8, too. You won't miss the 55-70 as you can move with your feet for that range. Just go for it.  

The 17-55 and the 70-200 are my two working lenses. With those on my pair of bodies, I'm set for almost anything.

 

17-55 has no f/stop ring... and the zoom is a little closer to the body...

I had the 17-35 and it was perfect for using the zoom

17-55 is a little awkward in the beginning, the extra 35-55 zoom is what I needed... no to get used to the close zoom ring

 

the 17-55 is better in low light for sure, the f/2.8 is quite useable. IT is a heavy lens, one that is not as easy as a "Carry-around" as the 18-780, which is quite petite in comparison.

If you want low light I would first add a $99 50/1.8 In my opinion f/2.8 is NOT fast enough for indoor shooting with no support and no flash, for the most part. The extra stop and a bit of a 50/1.8 or 85/1.8 will probably make the differencei n low light.

Not that I discourage buying the 17-55 it is afantastic lens, but Nikon erred when not including VR on this lens, that would have made it a low light uber-lens.

Overall the 17-55 will give you quality across the range and across apertures, the pictures really pop.