Motherboard showdown, nforce or ddr3?

Is it better to go for an nforce motherboard wich as far as i can tell offers little (except designed for 8800 series performance "increces" and auto overclocking through nvidia control pannel)or to get somthing with a p 35 or x 38 chipset and go for the faster ddr 3 momory

and just to check, crossfire support dosent mean i cant use nvidia sli with it does it?

thanks for the help.