Thanks for the heads up Alicarve, I'm looking for a good air cooler and you have saved me a lot of time and effort. I was considering the Noctua but can see that it won't fit with my ram 3 x 2GHz Corsair Dominator on a ASUS P6X58D-E MoBo.
I think Noctua shot them selves in the foot there, by not making their cooler just 1cm taller. After all it's designed for enthusiasts...and what kind of ram do they usually buy? High performance, and that's very often has high heatsinks.