im guessing i can use ddr2 1066, as i see some ppl are using ddr2 800 with a q6600 but is there much of a performance gain by using ddr2 1066 over ddr2 800?
I wouldn't go ddr3 especially if money is an issue. ddr2 800 should work fine as long as you don't plan on overclocking it past 3.6ghz (which is about the max you can hope for on air anyways), as that allows you to run a 400mhz FSB and run the ram at 1:1.
Buy some cheap DDR2 800 that comes with 3 or 5 year warranty.
Stuff like kingmax value memory will work just fine. No need to throw away money you wont gain anything by buying better memory.
My kingmax overclocks to ddr 900 speed without upping voltages.