Antec Sonata is the best choice. It is well built and designed for silent/quiet operation. Antec quality is amazing, the cases are tool-less chassis designs and have a look/feel that is second to none. You won't scratch yourself on sharp edges inside an Antec case since the edges are rolled and are very smooth. And that brings up another benefit, working inside an Antec case is a joy since everything is so well laid out and easy to take apart. The TRU-POWER power supply is very quiet near silent in operation.
Offcourse the loudest components in an Antec case will be CPU HSF, GPU HSF, and your Hard Disks. You can always tame them and you will no doubt want to since silence from a computer is like a breath of fresh air.