G.Skill Ripjaws X Series 16 GB (2 x 8 GB) 240-Pin SDRAM (PC3-12800) DDR3 1600 CL10-10-10-30 1.50V Dual Channel Desktop Memory Model F3-12800CL10D-16GBXL at Amazon.com
Kingston KVR16N11K2/16 16GB 1600MHZ DDR3 Non-ECC CL11 DIMM (KIT of 2) at Amazon.com
Corsair Vengeance Blue 16GB (4x4GB) DDR3 1600 MHz (PC3 12800) Desktop Memory 1.5V at Amazon.com