I'd get the cheap mobo the E4400 and DDR 800.
Well kinda depends actually. Do you want to OC. DDR800 is not much more than 533 / 667 hence why i recommend it.
But I can't spending more money in mobos with DDR2 support.
I dont want to OC. I'll run all in stock !
I live in Brazil. Here mobos with c2d and ddr2-800 are very expensives...