chazz469, i planned on using one on my HDD & another on my NIC activity. i haven't committed to any installation location on any of my PCs yet, but for my server i'm leaning towards mounting the 2 LED bars through the bay cover near the sides of my LED triangle:
the triangle has power, HDD, & NIC LEDs in it already, but i figured the dancing displays would add flare to my relatively boring case.
for my other PC (Antec 1200), i'm thinking of using all blue LEDs to match the all blue theme. i'm putting this off because 20 blue LEDs are expensive & my h2o budget is a top priority for now.
NOTICE TO ALL:
i replaced the input circuit (D11 & R2) with an affordable 4N25 optoisolator to make the circuit much safer for use with any device. with optical isolation, there is absolutely no danger of feedback between the device & the 4017, & the device is actually hooked up to a true LED (the device won't know the difference between a stock LED & the 4N25's internal LED). i'll update my schem with th 4N25 when i have time.