Your board will do DDR3 1600 max. So you can go with low cas latency DDR3 1600 for a slight performance gain or you can go with mainstream DDR3 1600 for a bit cheaper.
DDR3 1600 cas 7 at 1.5v. About as good as you can do with DDR3 1600. A few programs will benefit from the tight timings. $149. Lifetime warranty like with all GSkill RAM.http://www.newegg.com/Product/Product.aspx?Item=N82E16820231537
DDR3 1600 cas 9 at 1.5v. Much more mainstream and to be honest with a Sandy Bridge system all you need. Since you have an AMD system though the tighter timings of the above kit will be of more use to you. It will only be something you would notice in benchmarks and certain rendering programs that take hours. So for damn good RAM just not super high performance but realistically plenty in most situations is the for much cheaper. $89. Lifetime warranty.http://www.newegg.com/Product/Product.aspx?Item=N82E16820231429
There are also plenty of choices in between with some cas 8 stuff. Basically the lower the cas the faster the RAM all other things being equal. Is the cas 7 stuff worth the extra money? In my opinion only if you do video rendering and encoding. For gaming the 2 will perform identically.
Either of these RAM kits will fit under a large air cooler for overclocking the CPU.