I know that on a standard case, one would plug the case HDD light straight to the motherboard. Okay, So If you have 2 or more hard drives, and you want to know which one is being "accessed" where does one wire led's to? This is going to be more of an art thing than it is actually useful. For my custom case, it will have a standard on light and a hdd light, but you can flip a switch and I will place LED's along with the wiring, So that when hard drive one is being accessed, you can see the red lights follow the wire to the motherboard. Power will just be green LED's and a green LED heatsink on the processor.