if your going to be overclocking, the RAM speed is important, if your going to be overclocking a huge amount, you will also need very good cooling,
if you do not overclock, RAM that is over 1333mhz is pointless.
when you put RAM that is higher than the default FSB speed of the CPU and what is set in the motherboard, say you put in 1600mhz RAM and are not overclocking, your ram will run at the default speed set by the FSB in the bios, which will be 1333mhz or 1066Mhz, you will only get the 1600Mhz out of your ram if you overclock or change the settings in the bios.
higher speed RAM is not really worth the price, even if your overclocking, 1600Mhz should be more than enough to get a good overclock.
if your a programmer, the higher speed ram is of no use, you need more RAM not higher speed.