I'm searching for RAM too!

I think I'm going for the Crucial Ballistix, but I'm not out yet which I should choose:

2 x Crucial DDR2 BallistiX PC6400 1024MB CL4 BL12864AA804
or
2 x Crucial DDR2 BallistiX PC8500 1024MB CL5 BL12864AA1065

Which of the 2 will give me better performance / overclock?
Because the 1st is 800Mhz, but 4-4-4-12
The second is 1000Mhz, but 5-5-5-15

Anyone any idea which one is better?