I'm currently looking at the same sort of thing. Mostly stock cables now so room for improvement everywhere. My approach has been to prioritize what gets the most use and is the weakest link. Speaker cables get used by everything so does the amp power cord. Interconnect between pre and power amp or most used source would be next. Digital cable to DAC probably gets used a lot too. If I decide to further upgrade one of those then I'll move it down the line to another less used component and put the shiny new one where it can do the most. Now I just need to wait until the jar is full of nickels and dimes so I can pay 25% of my systems value in new cabling.
