Any RAM will do for SB, 1600mhz is the sweetspot though. Higher than 1600mhz the gains are minimal and for everyday things like internet and gaming you won't even notice the difference between 1600mhz and 1866mhz+.
For overclocking, with SB, RAM doesn't affect your OC capability. The BLCK will stay at 100 and you don't need to change it, you just need to set the multiplier and find a stable voltage.