Hi Keith12,
I'll do you one better and agree with 95% with what you said. lol, all jokes aside though, I initially suggested an 850w or at least 750w simply to allow room for expansion. Seeing the specs of the OP PC, I assumed that at some point down the road he/she may wish to add to it. Be it in the form of the above RGB/Watercooling/Fan Controllers/Temp Controllers/OC'ing/Other all of which would potentially draw more power. Would it draw an additional 150w? I have no way of knowing. True, the OP did ask for a budget PSU and so that statement alone may void my assumption that any modifications were forthcoming. I just personally like to side on the side of overkill vs "enough to."
A few months back I aided my neighbor in building his first PC. (Console Gamer) I suggested an 850w then as well and during the course of his own research, he said almost the exact same thing as you. I then said almost the same thing I typed above. He is, and i don't use the word lightly, a "master" electrician who works for the military. He started digging into what component used what amount of power under what load vs the Peripherals that he would have installed, Massive Case/RGB's/AIO/OC Etc. and my dumb brain couldn't grasp 1/2 of what he was telling me. In the end he got a 1,000w instead. lol..
good post.
Yeah, look, it's different horses for different courses.
The system defo doesn't need any more than 650w. You could add in 20 HD's/fans or any peripherals the OP would like, and nothing will use 350w of extra juice, never mid approx 150w headroom with a 650w PSU.
However, I would agree that having more is generally better, but not so much for an 750w/850w PSU. There is just no need in this case.
To the OP, yes, going gold is a good idea. Anything from the EVGA G2/G3 line, Corsair RMX/TXM, Seasonic Focus Plus Gold would be good. You really don't need anything more than 650w, but for the puspose of meeting in the middle, then a 750w G2/G3 or Seasonic Focus Plus is a good call. They all have 7-10 year warranties, and as MRGR74 has said, the PSU is as important as any other piece of hardware in a PC and is the heart that powers it.
BTW, I linked the Corsair above, because in India you have very limited availability for high end PSU's. This one is expensive enough, but is a good PSU.
It might be worthwhile looking at whatever online store you use, to see what's available, then we can better advise.