I was scoping out RAM for my new gaming build this morning, and thinking to save a few bucks I was going to go with DDR3 1066 or 1333 instead of the top end 1666 the motherboard supports. However, when I went to newegg, it seems that all of their ram from 1066 to 1666 is around $110-130 for 2x2GB. It seems strange to me that dropping down two clock speeds only saves maybe $10, so I feel like i'm missing something, as there's essentially no reason *not* to go for 1660-1666 RAM when the price point difference is nonexistent.
The RAM i'm looking at is This G.Skill for $110. Its listed as supported by the motherboard on the Gigabyte memory compatibility chart.
I also use the warranty as a factor, and look for newegg reviews that include my motherboard. The speed depends on many factors, including your bios adjustments. I like msi boards, as many of the new ones have built in memory ratios that are listed in manual mode. I use 1:1.66 and 240 for the cpu fsb for an easy overclock with no voltage increase. Your mileage may vary.