There are many approaches to take when building a PC. At the top of my list of priorities is silence. My current system consists of mid-range (for its time) hardware in an oversized case outfitted with large, slow-spinning fans and a solid state drive. There’s a massive twin-tower heatsink on the CPU that’s overkill for all but the highest-end of chips. The rig is still audible, but just barely.
While still sufficient for my needs, I’ve dreamed of building a truly high-end rig that is entirely passively cooled.