1) If you go for the i5 CPU, because you don't OC, then get the i5-3470 or i5-3450 if you can find them.
86 Processors From AMD And Intel, Tested http://www.tomshardware.com/reviews/cpu-performance-comparison,3370-16.html
2) For the RAM you want to buy 2x2GB (or 2X4GB) , becaue you need two double channel RAMs to run in double channel mode to get better performance. If you only one RAM that will run in single channel mode.
3) For RAM I will recommend get the 2X2GB or 2X4GB DDR3 1600MHz Cas Latency 9, the brand will be Crucial, Kingston, G.SKILL. Don't get the "Corsair Dominator 4 GB (2x 2 GB) DDR3 1333 MHz CL9 - TW3X4G1333C9D" that has high return rate.
Because the 1600Mhz CL9 has the better performance value, http://www.tomshardware.com/reviews/corsair-vengeance-crucial-ballistix-kingston-hyperX,2907-11.html