As an anarcho-communist, I have to say, I don't acknowledge property rights. Why? Because property rights boil down to "I was here first, I stuck a flag in it, it is mine", and everything had a flag stuck in it before I was born, and I refuse to acknowledge a system that considers all of this to be someone elses property. It is not. It is my birthright, to share with others of my generation. If you claim I do not have a right to my birthright, I consider that justification to kill you and take it by force.
As far as intellectual property and creative works are concerned, there are two ways to measure the value of those. The first way of measuring the value is to determine how much leverage you can achieve over your fellow man with them, how much they are willing to sacrifice to get it. That is a valuation based entirely within the system of property rights. But there is another way to measure the value. These types of works can also be measured in the advantage they bring humanity. The more people who are enlightened, entertained, educated, cultured, the more value.
The first type of value is entirely arbitrary. The intellectual work doesn't create the physical work that was used to pay, the amount available to pay was fixed before you came on the scene, and you will get less than is available, because the creator needs some too, and he's inclined to compete and give you as little as he can.
The second type of value, the real value, it is destroyed the more you restrict the propagation of the intellectual or creative work. Your neighbours become a little more barbaric, their lives a little more desperate, their minds a little more closed, their thoughts a little less effective. You cripple their capacity to be your allies and friends, and give them reason to wish to break the system and take the wealth that is being destroyed, because they know it's being destroyed simply because you would pay armed men to keep from them what it would cost you nothing to share with them.
Private property is a bad system. But intellectual property in its myriad forms is a needlessly destructive and utterly stupid system for any person to support who doesn't have harming their fellow man and keeping him small as an agenda.