I have the 16-35 and the 28-300. Find this combination to be a great combo and when traveling these are the two I carry. I also have 24, 50 and 85mm primes that are rarely used and only when wider apertures are required. I think you will find the sharpness of the zooms very little different from the primes, and, if you post process with a program offering lens corrections (I use Lightroom CC), I find the results very, very good. My other favorite lens is the 24-85 VR that was a kit lens with my D600, it is incredibly sharp, I think even sharper than the primes except for the 85mm 1.8. These are not the the holy trinity, but, having shot with the trinity, I think my 16-35, 24-85 and 28-300 offer me better range, lower cost and in some cases, better image quality. They are all VR and offer excellent value - you can buy all three for about the cost of the 70-200 2.8! That said, they are not pro lenses and are thus not weather sealed, not as robustly made and probably won't take the beating the pro lenses can. For me this is not an issue, YMMV.

Getting back to your question about a lens suitable for birthday parties I feel that unless you need higher shutter speeds for stilling subject movement, the 35mm f1.8 prime is probably not going to offer a meaningful improvement over the 28-300 set at 35mm. You would give up VR too, so camera movement will have more effect on the results if shooting slower speeds. The 35mm f1.8 cost about the same as the 24-85 VR zoom and I think you would be better served by the latter. That's my 2 cents worth - other opinions may vary :)

Hello all. Now I have this itch to buy the D750 and hence the following question. The 24-120 FX lens is actually ore expensive than the 28-300 FX lens. However, all retailers (Adoraa, B & H etc) have the D750 kit which includes the 24-120 lens for $2300. My question is whether they will switch the 24-120 lens to the 28-300 lens for the same price ? I will have more use out of the 28-300 lens.

P.S I already own D7100 with the not so useful 18-55 lens and 18-200 DX lens, 50mm 1.8 and 35 mm 1.8 lens.

Gobuster, thanks for your input. I am leaning to a 16-35 or the 17-35 and possibly the 24-85 VR. I mention the 24-85 because it might be a better all around walk-around lens. I find myself using my D7000 with the kit 18-105 more than my D750 with the 28-300 only because of the weight factor. I don't think that the primes will be all that much better than the high-end telephotos. I'm sure someone will correct me on this issue. But as far as primes are concerned, I think the 50 f/1.4 would be good to have but I don't think it would get used all that much.
-FiddleMaker

Thanks, glad my input helped. Regarding the 16-35 f4 vs. the 17-35 f2.8, I looked carefully when choosing and came to conclusion that the 16-35 was by far the better choice. Firstly, it has VR, and, believe me, that makes a difference even on a wide angle lens when hand holding. Secondly, it is far less expensive, but also a Nano-coated pro-lens. So, unless you really need that extra stop, I think the 17-35 is not such a good value. Both lenses have great optical performance with easy distortion correction in camera or PP.