you pc doesn't requrie a 880 watt psu. more power to you if you get it just for kicks. but a 600watt should be more then enough.
DDR2800 will give room to overclock the cpu. it's a shame not to overclock a q6600 to at least 3.0Ghz as it takes it so easily.
Unless you really plan to do sli get a intel board with a p35 or p45 chipset. Nvidia chipsets have been sucking lately. Also the radeon 4850 is a better video card. the intel board will let you do those in a dual card senario.