You have to pick that point, but I'd set it at 1600 CAS9 1.5v. Just look at prices.
"Regular" RAM like this need no fancy cooling. don't worry about heatsinks or fans except that you have enough clearance for your cooling.
quality is generally by brand. Pick someone you trust and has a lifetime warrantee.
Speed of RAM will give performance improvements, but they are VERY small. Like doubling speed gives maybe 2-3% real-world performance improvement in the average application for 3 or 4x the cost. RAM is a component you go cheap unless you are squeezing every last ounce of performance from the system. A light duty non-OC system should not be fitting that description. Find a brand you trust and buy yourself some cheap RAM.
There is one case and one case only where RAM speed may be worthwhile. Integrated Graphics gaming performance does see significant improvement with higher RAM speeds (but not too much with lower latency.) If you are gaming with an IGP, it may be worthwhile to move up to DDR3 1866 or 2133 or even 2400. In many cases though, it becomes just as economical to buy a low end discrete card and use that instead of spending too much on RAM. After all, if an $80ish card like a 7750 will outpace any IGP, why spend an extra $100 on fast RAM to squeeze everything out of your IGP?
