My computer is in a Fractal Define R6 case, M.2 drive as system, a big heat sink for CPU, two conventional HDDs in Silentmaxx HDD Silencer cases. The ladder don’t really fit into the case, build a DIY solution to iso-mount them. Super quiet system, barely audible. As my graphic needs are modest, I’ve chosen a passive graphics card but there are many fan-cooled ones out there that are very quiet with standard load. The already very quiet external HDD I’ve connected for backups is the loudest part of it 
i7-7820 x on an Asus Prime X299-A, running @ 4,5 GHz permanently.