PSU - In the Antec 1200 or DF-85, the CP-850 is a no brainer for up to twin 570's / 6970's with it's $115 cost and 10.0 jonnyguru rating but it won't fit in the other cases. For twin 580's ya would need the CP-1000. In the other cases, I'd look at the CorsairHX850, XFX Core Edition 850 (a steal at $90).
At 1000 watts, I'd skip the HX1050 becaiuse of its meager jonnyguru performance rating. The AX1200 is a bit pricey but so are all the other decent 1200 watters.
RAM - No, the tall toothy heat sinks will hit most of the better air coolers, but they are totally unnecessary. The only cooling effect of these big coolers is that they "look cool". While they served a purpose (when they were effective) w/ DDR2, they are absolutely useless on DDR3.
At more than 2" tall in certain areas the Corsair Vengeance could pose a problem for users like me who use large coolers such as the Scythe Mugen 2. I was able to use the Corsair Vengeance only after I mounted the fan on my cooler on the backside. Size is definitely a concern with heat spreaders of this size and therefore I encourage users to check that they will have enough space under their heatsinks before purchasing the Corsair Vengeance kit.
The problem I have with the Corsair Vengeance is the same I have with many kits of RAM on the market. Companies insist on putting large coolers on their RAM and it limits the choice in CPU heatsinks that can be used within users system. DDR3 does not require these elaborate coolers with its lower voltages which translate to lower temperatures then RAM saw during the DDR, and DDR2 era. Corsair is correcting this with low profile versions of its Vengeance line but ultimately I would like to see the average size of coolers drop instead of having to look for specific low profile versions of a memory line.
For gaming, grab 8 GB of the very same RAM but in the low profile version .... the ones the author above talks about Corsair "correcting". That will eliminate the interference issue and provide the exact same performance.
MoBo - You mentioned "future - proofing, but ya basing your build an a MoBo that only offers a 2 year warranty when just about everybody else offers at least 3 years. My money and confidence is with the guys offering 3 and 5 years....Asus, Gigabyte, MSI, etc. Yes, a 2 year warranty will undoubtedly lower the price, but XMas 2013 could mean buying a new MoBo.
But twin 560's top the single 580 by 40% (also tops twin 6970's by 5%) so it's a very popular choice of late at 1920 x 1200. However, with the hybrid 560/570 coming out on Tuesday, reportedly at 560 prices, I'd be sitting and waiting for that.