Well, first, what are you going to be using this system for? If it's for gaming or any number of other everyday tasks, you probably don't need 16GB and can save yourself some money on unnecessary memory. Particularly in gaming, once you have enough, more doesn't really make a difference, it's the speed (frequency) that will influence performance after you hit about 8GB.
Also, from what I can tell, the two sets you're looking at are CL8 and CL7. In most (not all, obviously) cases, you won't notice a significant difference between either of these and CL9. Regardless of whether you end up getting 16GB or something less, I would recommend grabbing a CL9 kit, since the cost to upgrade to CL8 or CL7 is exorbitantly high. Check out these benchmarks if you want some confirmation of this: http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/6
You'll notice (even in the CPU physics test) that it's the frequency of the memory, not the CAS latency that really makes the difference.
If you're set on G.Skill, I would recommend this set: G.Skill 8 GB DDR3-1600 Kit (Light-Retail, F3-12800CL9D-8GBRL, Ripjaws-Serie).
Also, Corsair makes good stuff as well: Corsair 8 GB DDR3-1600 Kit (Light-Retail, CMZ8GX3M2A1600C9).
Hope this was helpful!