Therefore with the higher clocked memory at looser timings you are barely slower on response and your throughput will be better. I don't know for fact this is correct but it seems logical to my mechanical brain.
If you plan to run stock speeds on the CPU, then get the CAS7 memory. However, if you expect to attempt to get a good CPU OC and higher memory speeds, get the 1333 kit.
In a nutshell, don't buy memory that will bottleneck your CPU OC.
I think my comments and Mike's can both be true. However what he is saying is more practically useful. If you are not OCing, then just get RAM to match what your CPU runs at stock.
From [H]s AM3 with DDR3 review http://www.hardocp.com/article.html?art=MTYyMSwsLGhlbnRodXNpYXN0it seems that the CPU bus and the memory bus are completely independent of each other. In this case your memory will not limit your CPU OC at all. If you don't do anything the memory should run at the SPD values. If this is the case I would recommend the 1333 CAS9 due to the time latencies I showed in my earlier post.
That being said I will know more in a week when my ASUS M4A79T Deluxe gets here so I can play with the 720 BE CPU that got here today. I got Corsair XMS3 1600 with the CAS9 for my system.