[bobkoure]

//edit by pH: off-topic stuff removed

Back to the original subject:
The Germans do seem to focus on quiet (Innovatek passive radiators, for example), and given water's specific heat, you really don't need a lot of flow to carry away the heat generated by a CPU. IMHO, the downfall of low flow is that the lack of volume/flow translates into a lack of velocity in the waterblock(s). And the downfall of quiet (passive or low airflow) radiators is that coolant is warmer. So you end up with a double whammy - less efficient transfer into warmer coolant.
But you get quiet. I like quiet. IMHO there's not lots of point in having a fast PC on/under your desk if fan/pump/disk noise is going to drive you to distraction.
Up to now, I've pretty much been following the German low-noise pattern (both for my personal PC and for others I've set up - including one in a recording studio) - but with 3/8" (9.53mm) ID tubing (German stuff seems to be 8mm ID). It does seem to work - even with overclocks and the occasional couple of hours testing at 100% load (SiSoft CpuBurn). I think what's going on is that as more heat is generated, the coolant temp goes up, which increases the temp differential between radiator and room air, making the radiator more efficient.
I've since switched my "main" PC over to 1/2" ID tubing, a slightly more powerful pump (1046 to HPPS) and BlackIce Pro to 6x6 heater core. An undervolted 120mm panaflo "L1A" fan, which had no problem pulling sufficient air through a BIP is essentially stalled with a 2" heater core. Stacking two fans got me to reasonable temps (CPU diode shows 5C cooler than with BIP, system only slightly louder). I'm now playing with cage blowers to see if that gives me a better flow-through-restriction / noise tradeoff. Of course, at this point, I'm not looking for a better overclock (limited to ~205MHz by system board anyway) but playing with what's turned into a fun hobby.