In an unrelated Internet forum I got into a discussion about hardware damage from forceful shutdowns (holding the power button for 5 seconds) and power failures. I was in the opinion that normal PC hardware does not suffer from this - after all, it's not much different than what they experience under a standard shutdown. But another person thought that it could do physical harm to the hard drive and possibly other components as well. He also said that the journaling features of filesystems are useless in face of power failures and were intended to help mitigate damage from system crashes.

Now... I think this is nonsense, but then again I lack the experience and knowledge to say it with certainty. Perhaps someone else is more knowledgeable in this area and can shed light on this burning issue? :)