Certainly the CPU and GFX would need to be w/c. It would be a good idea to w/c the NB as well.
You can still achieve air flow through the case with w/c by positioning an internal rad on the case fan holes. The rads fan will draw air into the case. Also, the
PSU fan will blow air out.
I use an external w/c unit which is normally very quiet even though it has 3 fans on the rad. 99% of the time they spin slowy with a low noise level.
What do you want the most? Low noise or low temps for overclocking?