Guys what DDR3 would you recommend for this?

Should I go for highend 2000MhZ? I have my eye on G.Skill PI 4GB G.Skill DDR3 PC3-12800 1600MHz TT (PI) Series (7-7-7-18) Dual Channel kit.

Not sure what to get. Can you please advise?
CPU will be QX9700 water cooled.

Thanks.