Hey hey, Im attempting my first build and these are the parts Im going to order. After months of research Ive come to the conclusion that these are the best parts for my budget. Without further ado I give you "the list" I will be building this sometime within the next 3-4 months.
get a different power supply: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
you may also look at getting an X38/48 MOBO and getting a 4870. I just saw the 512MB version for 215 or so after MIR, which one of those is a little better than the 260. Also, Crossfiring them would be awesome.
Umm...... You know you can't SLi that 260 on that board right? If you really want a 260 then consider looking at a 750i board. If you want to go with that MSI P45 board though you should consider going with a Radeon 4870 instead.
I'm also not crazy about that power supply. If you're only going to use one video card that get a lower watt rated, but better quality power supply such as this one.
As far as power supplies go, you can find better. Look for a 650-750 watt power supply. I recommend Antec or Corsair or PCP&C.
For motherboards, I recommend the Asus P5Q Pro. I believe the reviews say the ACF7P you've chosen works with that motherboard without any physical modifications to the fan or motherboard.
For GPUs, a 4870 512MB/1GB or GTX 260 (Core 216) will be fine. They all perform similarly, look for reviews to see how each perform on the games you play. You can't go wrong with either cards.
I also recommend getting a E8400, E8500 or E8600 over the Q6600 because they clock higher, and even when overclocking is factored in, they are better for single and dual core optimized games. (E8600 isn't necessarily worth the extra money, at least for some).
I personally have five to six Antec Tri-Cool fans, from 80mm all the way to 120mm. They simply aren't quiet enough for me at the low setting. They may be for you. They do push plenty of air, although they leave me wanting for more. Consider the S-Flex D or E model. Just have one fan in the rear pushing air out, and one air in the front pulling air in. Two fans pulling air in in the front is overkill and just makes your case detectably louder (it doesn't decrease temperature no where near as much as going from zero front fans to one does).
For the sound card, I think you will be fine with the onboard HD audio. You can always go to your local PC store and buy a Audigy for around the same price if the onboard audio isn't good enough for you.
Great choice on the hard drive. That particular one is on my list for upgrades as well.
Remember to give Antec's P180 a good look. That case is magnificent. The Corsair CMPSU 650TX and 750TX go well with it.