For me, my approach starts with the ride height and spring rate, moves on to the dampers, the anti-roll bars and tire pressure, then everything else.
I try to develop setups that properly absorb surface undulations while providing me with the kind of characteristics that match my driving style.
The essential thing is having a car that can cope with the requirements of a particular course, in my opinion. I admit that I am pretty lazy though :P
As far as drifting goes, I focus on stability during various conditions, like hitting feelers and grass.