Get the AP-15's you won't regret it. I remember frozencpu has some in stock or aquatuning($14 a piece, but have to buy more than $75 dollars worth to get cheaper shipping)
The h100 is pretty good from benchmarks and reviews. I would say they make blows to each other in terms of different settings. Maybe the Noctua performs better under load than the h100, but the h100 has better idle temps.
Yah, something doesnt sound right with your idle temps. Have you tried reapplying TIM to it. Dont do it if your warranty is still intact. Just RMA if it is.
Yep if your resolution is only 1080p there is no reason to get crossfire/sli. Just get the best card your money can buy in a single gpu set up. 6950 2gb is great because of unlockable to 6970 and 2gb vram
Crossfire is fine for eyefinity.
I would recommend reference 6950s unlock to 6970s for best bang for performance especially with the 2gvram.
Usually new games come out with sli/crossfire profiles quite soon after release if not at release. Older games probably do not support crossfire and may...