Answer: One is slacking off, and the other is a respectable productivity tool.
My grandmother took a "power nap" every afternoon, but she didn't call it that. She hit the ground running by 6 a.m. every day, but her afternoon nap was also part of her daily routine. From what I observed when she stayed with us, she'd usually doze off while watching her favorite soap. Of course, by then she'd accomplished in a morning what would have taken me a full day.
If you need something more sophisticated than "As the World Turns" for your daily "power nap," the audio files at Nap Sounds might be just the ticket for you. Of course, if you're working in a conventional office with a conventional boss, none of this may be very practical for you. "Power nap, my @!*#%. Get back to work!"