Which Dominator RAM for P6X58D set up?

I'm struggling to decide on which RAM to get from the following list for an intended ASUS P6X58D Premium board set up?
TR3X6G1866C9DF CAS 9-9-9-24
TR3X6G1600C8D CAS 8-8-8-24
TR3X6G1600C7D CAS 7-7-7-20
CMP6GX3M3A1600C7 CAS 7-8-7-20

Any comments would be much appreciated thank you.

based on what criteria?

workstation?
gaming?
benching?

the 7-8-7-20 looks good to me!!

If you are willing to spend $250 bucks on 777-20 @ 1600mhz, Id go with the 8-8-8-24 @ 2000mhz.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820104122

I7 benefits more from from the speed than the timings. Although this is solely based on the assumption (I know, assuming is bad) that you will be overclocking. 2000mhz RAM will ensure that you can go up to 200 bclock w/ a 2:10 divider setting on the RAM (2000mhz @ 200mhz bclock). Also, it should give you the option of going to looser CAS9 timings and getting a bit more if you want to push the bclock higher than 200 (most people run 200mhz for a cool 4 or 4.2ghz *21 or 20 multi*).

2000mhz is overkill and you won't even notice the difference in speed

2000mhz is overkill? Says who? Depending upon what he is doing. If he wants maximum performance, is going to be doing benching/crunching, things of that nature, why wouldnt you want 2000mhz? I wish I had gone w/ faster than 1600mhz RAM with my previous i7 system.

Kingston makes some good RAM, and unless he has his heart set on Corsair, Id definitely take the speed w/ CAS8 Kingston over the 1600mhz CAS7/8 Corsair.

Again, would be helpful to know what the OP has in mind as for using the computer.

ok doz I see your point and I agree. kingston does make GREAT ram!