i7-6700k with for cores is much better than 5820k in pure gaming, benchmarks releases some week ago stated that last intel I7 performs equal to 5960x in gaming.
If you don't do rendering, editing etc i suggest to get the i7-6700k
In summer Nvidia is releasing new gpu generation, buying gtx980ti atm isn't that wise
i7-6700k
asrock z170 extreme 6
corsair vengeance lpx 3000mhz 2x8gb
decide what to do with the graphic card. You need a 980ti only if you buy at least a 2k monitor
samsung pro 951 250gb
WD blue 1 tb 7200rpm
Evga supernova g2 650w (for 1 gpu) or Antec HCP 850 (for 2 gpus)
Cryorig R1/ Cryorig A40
NZXT H440
with this build you save a lot of money probably 1000$ and have same results
for a 1080p monitor a r9 390x is a good...