A single 570 with the option to add a second one later will run a lot of games for quite a while, so the 570 is a good choice.
G.Skill RAM isn't the highest quality RAM - it only gets purchased a lot because it's usually a little cheaper (I have it myself). The Corsair RAM is a little better and Crucial is probably the top name in memory.
The Spinpoints are a good choice but if you want to use one of them as a backup you should look into RAID1.
In terms of motherboards, first you pick a chipset...the P67 and Z68 being the popular choices. Z68 is about $30 more for onboard graphics and SSD caching which makes no difference for gaming. Also make sure your motherboard supports two PCIe 2.0 x16 slots in either x8/x8 or x16/x16 configuration. The cheapest motherboards I would recommend for your needs are as follows:
P67: ASRock P67 EXTREME4 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Z68: ASUS P8Z68-V http://www.newegg.com/Product/Product.aspx?Item=N82E168...
There are more expensive ones depending on what features you want and what you can afford.
Why does he need the highest quality RAM? Kingstons, G.SKILL, and Corsair are all top manufactureres. Not many people buy Crucial ram anymore but if you mean memory as in SSD then Crucial M4 series are good SSD. You should take a look at tihs for $50 only: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Danraies offer good choices for motherboard. You pretty much only need dual x8 slots and a decent amount of usb/sata connections. Those are the key features you should be focusing on. As for the SSD. I think 64gb is enough as a boot drive and storing some games. Windows 7 will take around 20GB. The 128 has better performance compare to a 64gb by the way. Tom's did a review on it.
I second the choice of the 570. You are getting a 850W psu and 750W is enough for full system load with sli 570. Pointless to get that much power and not use it but hey.. some people sleep better at night knowing they have enough power to run their rig .
boards with the P67 chip are usually easy enough to overclock but the features that the manufacturer puts in the bios are important, too. For example I have an asus board and I had no problems overclocking, msi boards are supposed to be easy enough, and I've heard that gigabyte boards lock some of the voltages so that it's harder to overclock (though I don't have any personal evidence for msi and gigabyte). I don't know about ASRock, though.