It isn't anything ground breaking but I'm always looking for a red post to lend me credibility. An alarmingly high percentage of people, for whatever reason, assume that Lich Bane's Unique Passive will translate into bonus magical damage. I've had arguments about this with a slew of people in the past and I am bound to get into it again. Lich Bane's in game tool tip reads "+350 Mana +80 Ability Power +30 Magic Resist +7% Movement Speed UNIQUE Passive: 100% chance when an ability is used that your next physical attack deals an additional 100% of your Ability Power in damage. This effect has a 2 second cooldown." I present you with a red post I can proudly display here like trophy that I can flaunt off to those non believers.
"Ranged attacks proc it, but be aware that, even though it's based on your AP, it's physical damage, so it's mitigated by armor."
-WhattayaBrian, Engineer, via the official forums.