I need a new mid-tower case for my new build. It has to have good airflow, because I will be OC'ing. I also has to be silent. By silent not only do I mean silent fans, I also want sound dampening materials like rubber around side panel and HDD mounting to prevent vibrations.
You will find no case that is silent while offering good airflow to help with overclocking, you may find some that are more or less quiet, but silent, no.
Possible options for you could be the 18x as already mentioned by 13hmonkey, another could be the Cooler Master Cosmos