Hi just wanted to ask a perfect PSU for my rig from all sifu2 here

CPU - i7 4790k
Fan - CM hyper 212X
MOBO - Asus z97 pro
GPU - Asus Strix 980
RAM - Corsair DDR3 Vengence Pro 8GB (2 x 4G)
HDD - WD 1 TB 3.5 inch 7200RPM
ODD - Samsung DVD-RW 24x SATA
CASE - CM HAF X
PSU - ??


im planning to run a single GPU config atm but maybe planning using a dual GPU config in the near future after the 4k monitors price go down in the market. well which PSU would be best ( and for future upgrades as well )