The 6600k is the most popular processor for gaming as the 6700k's HT capability and small performance edge many feel ain't worth the price premium and therefore many will say that the 6600k is the "best Skylake CPU "for the money". The 6700K is the best Skylake processor. Skylage CPUs use Intel 100 series chipsets (Z170, H170 ...)
https://en.wikipedia.org/wiki/Skylake_(microarchitecture)
Coming up we have Kaby Lake ... which will be supported on Intel 200 series chipsets .. these are expected to arrive Q4 2016... the Kaby Lake 7700k (Z270 chipset) will replace the Skylake 6700k and the 7600k will replace the 6600k
https://en.wikipedia.org/wiki/Kaby_Lake
At the present time, we have Broadwell-E processors (X99) that are faster in workstation type applications. These would include the i7-6950X, i7-6900K, i7-6850K and i7-6800K but again, you said best Skylake processor and these are not Skylake. Many folks will invest in this platform thinking well if it's best for certain workstation apps, it must be best for Office / Desktop apps and it must be best for gaming. This is false.
While X99 based Broadwell-E CPus would be best in system w/ 3 or more 9xx series GFX cards, with 1 or 2 GFX cards, the 6700k is, more often than not, faster than Broadwell-E. Selecting a processor for best performance is actually application specific. To answer your question as I think you meant it you would have to:
a) Change topic from "Best Skylake Proocessor for Productivity" to ""Best Proocessor for Productivity" or "Best Proocessor for Productivity which will be available in next 3 months"
b) name the specific applications of concern