If you get the non K 6600, get a H170 or B150 motherboard. No need to pay so much extra for the Z170.
The Corsair VS550 is not very good. I highly recommend a better psu. Seasonic S12II 520w or 620w would be great.
As far as the gpu, depends on your budget. I would at least get a GTX1060 6GB if not a GTX1070.