I know that throwing things cause damage, but if I were to pick up a metal box or a dumpster and drop it from a few stories up onto someone, will it do any damage?
And if it does, does that count against a pacifist play-through?
Can you kill people by dropping things on their heads
deus-ex-human-revolution
Related Solutions
If you kill people from range you are potentially missing out on XP, because:
Neutralize an enemy: 10XP
Hand-to-hand takedown: 20XP
Non-lethal: 20XP
Headshot: 10XP
So a non-lethal hand-to-hand takedown is worth 50XP, where just shooting someone is only worth 10XP (or 20XP if it was a headshot) and a lethal hand-to-hand takedown is 30XP.
However, playing non-lethal is more difficult as enemies can be revived and traq darts are slow to act (so non-lethal at range needs careful planning), and only using hand-to-hand takedowns means you're more likely to be spotted or trip an alarm.
Remember that you can get the Ghost (500XP) and Smooth Operator (250XP) bonuses for completing objectives undetected and without alarms (respectively), and I imagine they're usually worth more than the few XP lost by not taking down everyone hand-to-hand, so do whatever you need to do to avoid being detected whenever possible.
You might find What actions give XP in Deus Ex: Human Revolution? helpful.
Best Answer
I had to test this for myself, and here's the result:
As you can see, he is clearly dead, so do not try to climb to the top of a building, and throw things down on people! And yes, that would count against the pacifist achievement.
Note: I did it for science!