8 GB RAM is plenty of RAM for all but the most demanding of applications. 16, GB is overkill for most situations, and realistically, no one ever really needs 32 GB RAM.
What will you be doing with this system?
In the meantime, the best memory for your system is 1600 MHz @ 1.5 volts with a CAS of 9-24.
Ive got a asus rampage 2 gene, i7 920 and 6gig of OCZ ram and its still a bit slugish. Could i buy 2 single sticks of the same ram for that motherboard?