Just get cheap ram(low profile heatsink) unless you want to OC the ram(tall heatsink ram) which I don't recommend because it's quite pointless.. If your just going complete gaming then get 8GB of RAM and also get a GTx 660Ti if you can!
Is that a Corsair gaming series power supply? If it is not switch it to a Corsair one or a Seasonic.
You will be ok with the XMS line from Corsair for memory. Or some cheaper Kingston or Samsung memory. 8gb will probably do it for you, if not you can always update later with another 2x4gb kit. And be sure it is low profile memory so it can fit under your CPU cooler.
Would cheap ram be considered like 8GB for 55$ or 2x4gb sticks for 65-70$?