The problem with this whole issue is that we're defining morality according to compatibility with the operations of a system, and that system has recently become incompatible with reality. Thus, the entire debate is founded in a flaw, and we really need to direct our attentions to the more underlying issues.
Capitalism is a guiding principle for the allocation of resources to the people who will do the most good with them. This principle is founded in the assumption that those resources are limited. As relates to information, this has become almost completely not the case. So now we're stuck with a situation where our way of living is entrenched in a system that is limiting potential good for all of society, and those limitations are becoming increasingly obvious. Yet to not enforce those limitations punishes the source of that potential good (the creators), who still have to live within a system that only allocates resources necessary for survival according to the scarcity of what they provide to others.
In other words, the system is completely and utterly broken. It is incompatible with the potentials of modern technology. We either restrict humanity's potential by forcing artificial scarcity of information or we remodel our way of life. This, at least, is a very clear-cut choice.
This becomes especially obvious when we shift our focus to other areas of intellectual property law besides the strictly cultural. One very strong example is in medicine. Millions of people die because pharmaceutical companies develop medicines and retain the exclusive right to produce and distribute them according to intellectual property law. If not for IP law, generic brands would be able to sell those drugs for much, much cheaper to people who desperately need them as a matter of life and death. Theoretically, that would cut into the profits of the company that originally created those products, affecting their ability to develop more medicines. So there is some grey area there, but just how much one thing justifies another is very highly debatable. There are very similar things going on in food & agriculture, where there are debates raging over how IP laws should apply to genetic code, and it's an issue where large numbers of lives are at stake.
Let's apply these same issues to software. Can you even imagine the renaissance that could be ushered in by making all software freely available to everyone? This is stuff that costs nothing but electricity to reproduce and distribute, and every person with access gains an increased ability to contribute to society in return.
Information is really unique, because its value is proportional to the number of people who have access to it. Other things decrease in value as they become abundant. Information increases in value. This applies to every kind of information.
In the case non-cultural information (software, inventions, etc), the more widespread license to this information is, the more people can benefit from, add to, diversify, correct, and be inspired by it. This is only a good thing.
The inherent value of culture is in shared human experience. The more it is shared, the more valuable it is. Even the creator of a cultural artifact (book/painting/song/dance/whatever... I'll call them cultural artifacts) gets to enjoy the process of sharing their thoughts with the world. This is why people make such a big deal out of getting credit for their work, even in the absence of any material compensation. There is a thrill in being recognized for creating something; for having people know that the world was enriched through exposure to some piece of your mind. Audiences grow as human beings through exposure to new ideas and perspectives, or simply get satisfaction from knowing that someone is out there who understands them when they find a deep relation with some work of art. Beyond that, people bond with each other through shared culture. What do people do to get to know one another? They talk about stuff they like. If they like the same things, they rejoice. If they haven't been exposed to the same things, they make every effort to share and grow closer. How much more do you enjoy a book or a movie if you know someone else who has also read/seen it and talk about it with you? How much more do you enjoy a game according to the number of people you know who have also played it or can play it with you?
Sharing is the essence of culture and fundamental to human relations, and it's being stifled by increasingly restrictive IP laws.
There's also the often ignored fact that commodification of culture is a very new thing. It began with books, but that was incredibly limited in scope. Prior to the 20th century, most types of cultural artifact (paintings and printed text being the only exceptions I can think of) were organic, constantly evolving, memetic, very social in nature, and while attribution might be recognized by scholars, they were not owned or controlled in any modern sense by any entity. Stories were simply told, for various reasons, and changed a little with every generation and locality they spread to. It was the same with music, dance, stage performance, etc. Then we developed the ability to produce all these different types of media, and that process of production turned these things into commodities. The ability to intentionally produce culture for a living expanded, and it began to involve all of these middle-men in the process who needed to be compensated.
Now we've had another incredibly rapid change, where we still have this expanded media that has thoroughly saturated our way of life, but the justifications (due to scarcity) and processes of commodification which were developed over the last roughly 100 years have become almost completely obsolete. The middle-men whose livelihoods have become based on it are fighting desperately to maintain their relevance. The lines between professional and amateur creators have also become very blurred, and those actually trying to make a living as content creators are having to compete more and more with skilled hobbyists and aspirants.
Above all, we all have this feeling that there's something just plain wrong about denying people of an infinite resource, especially when its proliferation increases its value. We want to share these wonderful tools and cultural experiences with one another, but we're trapped by the foundations of a society that punishes such generosity. We're going to be so confined until we re-think the core principles by which we operate.
Some other thoughts a little more grounded in the way things are now:
Publisher contracts are often incredibly predatory. Especially in the music industry, I don't feel bad at all about not buying albums, because I know that the actual artists responsible for making it see almost none of the money from sales anyway. Major record labels are known to charge musicians for the process of making an album, and then offer only a dime or two to the musicians for the sale of that album. Only the biggest stars make any money from them. Most make money from live performances and merchandise, and putting out an album is seen as an advertising investment. If I want to support a band I like, I will pirate the album and then buy some merchandise, see them live, or just donate some money directly to them. Unless it's an indy album under a small or independent label.
Publishers stifle innovation because they don't like financial risk.
Current IP law leans towards giving publishers the ability to steal from creators. If you make some character, story, song, etc while working for a company and then leave that company, chances are that company retains the exclusive rights to your creation. Some contracts go incredibly dystopian. My degree is in New Media and included a class in IP law, so I'm actually versed in this on a basic level. We were warned about some companies trying to force contracts whereby anything you create while under contract belongs to the company. If you're a writer and you go home and write a story on your own time, unrelated to your work with the company, and then try to publish that story, even after you've left the company, they can claim the rights to it. Some even go so far as claiming the rights to your creations if they can prove that you had the idea for it while you were employed with them. The notion is that while you were employed with them, you had an obligation to submit any and all of your creative fruits to them for their profit.
It may be argued that file sharing has cut into the profits of big-time artists, but at the same time, it has offered unprecedented opportunity to small-time artists. It's made production tools and distribution channels both broadly accessible. Indy and amateur content is booming. The music industry is so much more colorful than it was 10 years ago. I'm fucking loving it. Metallica (fuck them forever for their treason) may have lost some money, but now The Faint can make it completely on their own. It's wonderful beyond words, and by god I'll fight for it.
This is not something I can substantiate, but I've heard a few times that most of the war on file sharing is war by traditional media industries on amateur content. It competes substantially with their former monopolies on the media, and they're responding by shutting down their distribution channels.
Oh yeah. And a few have mentioned try-before-you-buy as a justification for piracy. I was severely disappointed with Oblivion and Fallout 3. I wasn't planning on even trying Skyrim. Then everyone I knew started raving about it. So I decided to give it a chance. It's the fourth game I've ever pirated. I now own a legitimate copy, as well as a couple co-workers who also weren't interested in it, until I passed them my pirated copy. So there's my anecdotal confirmation of that little bit.