DDR3 Memory on the GTX 260

Also, keep in mind that you can NOT SLI on that mobo as it has an AMD chipset. You can only do crossfire(i.e can use 2 ati cards).

But if you are gonna use only one card then it does not matter which card you use, nvidia or ati, both will work just fine..
 
ddr3 on your card will run by itself so its all good, its actually supposed to be gddr3, which isnt even the same as ddr3 anyways. and hellraisers right no sli, i would reccomend getting a sli mobo or an ati card
 
About my psu...Im going with Corsairs 650w, I think that will suffice. I would go for the 750w but Im on a tight budget and I think thats a bit overkill.