If having a full 16 PCI-E lanes available to your graphics card and USB 3/SATA 6 Gbps support is of utmost importance then I'd recommend going with a Core i7 9xx processor instead. The Core i5 7xx processors from the Lynnfield family support a maximum of 16 PCI-E lanes so the design of the processor itself is limited to only meeting your minimum requirements. I kind of understood that before but after researching this I better understand why these new high-speed data connections have to "borrow" PCI-E lanes. Bloomfield processors like the Core i7 950 on the other hand can support up to 36 PCI-E lanes (source: Anandtech
). Of course this may seem like overkill since all you want is 16 PCI-E lanes for your graphics and however many additional PCI-E lanes to support USB 3/SATA 6 Gbps (maybe 4 lanes?) but those are the choices Intel has provided. I'm sure AMD would love for you to consider their processors as well. (for the record, I use Intel CPU's but don't consider myself an Intel fanboy)
Intel Core i7-950 Bloomfield 3.06GHz 4 x 256KB L2 Cache 8MB L3 Cache LGA 1366 130W Quad-Core Processor BX80601950
ASUS Sabertooth X58 LGA 1366 Intel X58 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
G.SKILL 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit Desktop Memory Model F3-12800CL9T-6GBNQ
TOTAL = USD$590
Your listed selections for CPU, main board, and RAM total up to USD$445 so for an additional $145 you get a faster processor out of the box, an additional 2 GB of RAM, and uncompromised support for USB 3.0/SATA 6 Gbps. Just food for thought. I don't know how much the USB 3/SATA 6 Gbps is worth to you.
As for my opinion on GTX 470 vs GTX 570, to me it's an easy call if one doesn't yet own a Fermi-based graphics cards. I'd go with the GTX 570. I've always viewed the original GF100's (GTX 480, GTX 470, GTX 465) as beta GPU's. NVIDIA was already way behind AMD on releasing their DirectX 11 products, couldn't afford to delay any further and released what I view as a substandard product. NVIDIA didn't get everything straightened out with their Fermi architecture until they released the GTX 460 and even then they only released a handicapped version of the GF104. In short, I think the GTX 570 is what NVIDIA should have released as the GTX 470.