Looking through that, it all seems to fit. If you don't have to worry about monitors and such, I'd definitely get the 8 gigs RAM if I were you. RAM's so ridiculously cheap right now, it's not even funny, and the speed increase is significant.
I'd also go for a second GPU if I were you. And yes, that "GPU" is in fact the video card. That would put you at ~$1001 before shipping, which is so close to your budget that you could literally pick the extra up off the street. Can't really help with card quality, though; I'm an ATI guy, and don't really know much about the quality of the various nVidia cards. Keep in mind, though, that with SLI, you have to use all the same card (for example, you can SLI as many GTX 560 Tis as you want, but not a GTX 560 Ti and a GTX 560).
That said, you do realize that that HDD only runs at half the speed the motherboard supports, right? Your motherboard has three 6 GB/s SATA ports, but the HDD only supports up to 3 GB/s. Might want to look at a faster drive, depending on how much you plan to move files onto, off of, and around on your computer. You could also run a RAID array - the motherboard can support a six-HDD array with 2 6 GB/s disks and 4 3 GB/s disks - but that might cost a couple hundred extra dollars, and quite frankly, it's unnecessarily complicated and a pain to set up.
That CPU looks pretty good, but if you want to overclock it, you're going to have some issues. It's locked, so your can't exactly push its limits. On top of that (no pun intended), the default fan is apparently terrible. I'd suggest definitely buying a different CPU fan for that thing, even if you aren't going to overclock it. It might mean you have to drop something, though, whether the second GTX 560 Ti or something else. Unfortunately, you can't just start with a 560/TI setup and switch to Ti/Ti later, since you're using SLI rather than CrossFireX.
Few more important things to consider. First of all, you forgot a DVD drive. Cases don't just come with those, you know, any more than they come with HDDs. You need to actually buy any drives you want separately. Second, look at the case measurements and your card measurements to make sure that your GPU fits in your case. A lot of the newer ones need a larger than standard case. Third, I don't think you're gonna get more than two GPUs in that motherboard, so you have very little upgradability past dual SLI without completely changing to higher-end video cards and leaving your old ones out of the build entirely (which of course you have to do when you upgrade card level with SLI anyways, but with this build, I don't think you're going to be able to upgrade anything but card level if you have two GPUs). Fourth, the 750W PSU should be fine for what you have here, but if you ever decide to add in a lot more HDDs and/or GPUs, you'll probably need to go up to a thousand-watt PSU.