Which of these is better RAM?

Agreed, the 2666 for the cost isn't even worth considering with a $4 price difference. Nothing wrong with the 3200 stuff, its just the same performance as the 3000 but with an added price increase. If you were to try and OC these sticks past their rated speeds things may change but thats a whole different matter.
 
Are you OCing the CPU at all, (asking as you may well need a bit of an OC to run 3000 or 3200. Of the three sets the best performance will be the 3200/16, very slight but the higher data rate will overcome the slightly lower CL of the 3000 sticks
 
so which will be better for gaming? The lower latency or the higher frequency?
i dont mind paying a bit more either

BTW i will be overclocking the cpu to hopefully 4.5GHz but i will have to wait and see if i get a good ticket in the silicon lottery.