First you decide are u gonna CF or not if you gonna Cross fire do get better smps.. More wattage the better.. your system will breath easy.. you never know the future.. So get 1000w one when you do have about a lakh budget dont do kanjusi here . Just a single ati card if you find the fps not great get one more simple.. Asus mobo i suggested has both cf & sli both run @16x ,has one more slot which runs @4x ( if at all you buy a physics card in future ) i think you wont require it.. . has tripple channel too. Very good mobo.. i am not sure about gigabyte ..
yeah if your going with nvidia in future they come with power hungry cards.. so better opt for 850 orr 1000 w smps..