Well, I don't need an especially fast CPU, or high performing GPU -- so, the A8 seemed like a good compromise. The onboard graphics should be more than equal to anything I throw at it. However, I would like get the most out of it by minimising bottlenecks in the rest of the system. Hence the SSD for speed (as well as for low noise, of course) for the OS and the 1866MHz memory.
OK, I think I understand what you want to do and I think the A8 is not a good choice. It's inferior to equivalently-priced Intel CPUs, especially for efficency which is going to affect the noise. It would be nice if you had a use for the GPU but it sounds like you don't. "Compromise" sounds good in the mouth of salespeople but if you're trading something useful for something useless, it's a ripoff. You might actually do better with a cheaper Intel CPU.
The memory speed does not make much difference when compared to the differences between CPUs.
You need enough memory for what you want to do however (swapping is slow, even with an SSD) but you can easily upgrade the RAM after noticing you could use more (not so with other components).
I took another look and realised its 'only' 3Gb/s, when there are 6Gb/s connectors available ... higher transfer rates
More than 3Gb/s is useless and the transfer rates you see are not much better than lies.
That said, the Intel 320 is slower than most equivalently-priced SSDs, just not as much as you might think. If you want to understand SSD performance, you have quite a bit of work ahead of you.
In any case, I'd still avoid Sandforce drives like the one you noticed even if they seem to have less problems and performance bottlenecks than they used to. A lot of people here recommend the Crucial drives which seem pretty good. I'd still go with Intel because I'm conservative when it comes to data.
certified "80 Plus Bronze", which implies a minimum of 82% efficiency across the power demand range.
That's unfortunately not true. Check the reviews to see what kind of efficencies you might expect.