One of the things that I'm sure we all will agree on, is that if you want an internal water cooling solution (inc radiator) its hard to find the space inside your case.
I'm not currently aware of any manufacturer that has teamed up with a case manufacturer. It would be great if a case came with the necessary holes and mounting points to make fitting a watercooling solution easier.
I like the idea SwiftTech has on their site, where the radiator sits outside your case, but attached to the back panel. That means that the 2 120mm fans cool the radiator, but also stimulate case airflow. The problem is trying to find a case that you don't have to cut in order to do this......