Being overkill depends on the parts you use in the pc and if you aim for crossfire/sli in the future.For a single gpu build would 650watt already be overkill.
But if you want a 750watt psu for a build with just one gpu in it be my guest.Might want to look at a gold or platinum rated psu so that even when on lower loads it's pretty efficient.
With how these psu's are build right now you probably won't hear it since with the loads you would have it wouldn't put out heat much so no use of the fan necessary.
Corsair do make have pretty good options as well with the RMi/RMx series.Can look at those too.