South of 70C is something a quality air cooled GPU should manage. There it would be simplest to pay more for a better cooler up front. Nvidia, and most of the vendors, set the throttle limit at 84C, though the GPU is good to 90C+. They are pretty much accurate with the stock TDP, so at 120W for a 1060, and little voltage changes allowed, they probably don't get past 150W or so.
Depends on the CPU. I know a decent Haswell/Skylake/Kabylake CPU will easily reach 150W real dissipation under a full load and the highest acceptable voltages. FX CPUs can easily break 200W, and the 9000 series comes at 220W. Ryzen is a little new, but from what I have heard the numbers that AMD provides are way too optimistic, I would expect numbers similar to Intel under overclocking conditions.
If cost is the primary concern, don't water cool. Just crank the fans up.