Yep - They're the dogs, but you need plenty of them. I was running 10 to cool a Prescott 560 (at 4.2GHz - possibly the hottest CPU ever until Wolfdale) with 4 more to cool the Graphics (7800GTX) and two more to cool the chipset.
You need all the pump capacity you can get (DDC2 18W or better) and the more 'buffer' you can supply in the form of a big passive reservoir also helps enormously. You do need to mount them vertically as well. Mounting them horizontally (in hindsight - it's obvious!) stops airflow through the fins so it just heats up. You also need to use 3/8" piping to match the inner diameters and quick-release couplings are an absolute requirement if you ever want to take the side panels off your system again sensibly.
You could probably get away with 6 on an M0 E2180 if you weren't overclocking, but anything more than a dual-core and you're you're going to need 10-12 sticks. They work exceptionally well, but you can't defy the laws of physics. And don't underestimate the size of them. They're 42cm high with a further bit top and bottom making them near-as-darn-it 50cm tall in use so you need a big case to mount them to. Coolermaster Stackers and Lian Li V2x00 series work well.
The temperature of the room is also of vital importance as you need a temperature gradient to work with. The colder the room, the better they work (again, you're probably thinking that's obvious).
I did look at bolting 12 of them on an outside wall and pulling the pipes back into the house, but in the end I just decided air conditioning was a better long-term option. It cost me about £2k to properly air condition my office at home, but it was worth every penny.
Silence is golden though. The Rasta colour option is possibly one to bodyswerve as it looks hideous in the metal.
