The Black Ice rads are great when space is at a premium, but if I were trying to build a silent system I would get the biggest heatercore that I could fit.
Big heatercores with low flow resistance are your friend. If the core will fit 2x120mm, then you can probably get better performance at a lower noise level with 2 7V (or less) fans than with 1 120mm at 12V. I like the 1970 Blazer w/o A/C myself:
You might think that such a huge rad is overkill, but with very quiet fans it is your best bet. You can see the 6.75" Rotron fan on top of this core; it is a 24V fan I run between 9 and 12V. I like the Rotron but it isn't exactly a silent solution even undervolted
Avoid Rio pumps; they are noticably noisier than the Magdrives.
NB/GPU/hdds? Gonna need a big pump to move water through all that. I would skip the nb and hdds and only cool the gpu if you have a need for it. The GF3 I have does get damn hot though, and I have an innovatek gpu block for it that I like a lot.