i would go for x38, afetr having my 680i and its so called 'fsb holes' i would never get a nvidia board again at leat untill i hear nothing but good things about it.
fsb holes => its really wierd in certain fsb speeds i cannot even post the computer. im pretty sure with my 680i and q6600 G0 i cant post between 3.3-3.5 which is really annoying if i wanna go higher its straight to 3.6