Ah then my recommendation based on him stating that he's a gamer, and makes no mention of anything else, is to stick to 8 gig as any more is probably overkill. But if you want to go to 16gb for another $15-20 I could see that. That's how I ended up at 12.
The two sets I referenced would be fine.
For SB (iX-2XXX) CPU and no OCing the CPU stick with the 1333 as 1600 Voids wanantee (Only a concern if you have to RMA CPU (applies only to a Intel system).
If for an IB (iX-3XXX), or an OCed SB, go with the 1600. CL9 or CL10, the ONly way you will EVER see a diff is if you run a benchmark - Real life you will NOT see a difference. That said if only a couple of bucks diff in price, he$%# go with the lower.
Again only applies to an Intel set-up