I have noticed the past few weeks that both my Internal and External drives are spinning up when I try to access them (like they have gone to sleep)? Energy Saver is set to "NEVER SLEEP"... what is going on?
I don't currently run 10.8, but in previous OS's (or at least in 10.6 and prior), there's an option in Energy Saver to "Put the hard disk(s) to sleep when possible". If this option is available in your OS and if it is checked, un-check it and that should fix the issue.