It's easy to think that when it comes to Apple vs. Psystar, that it's going to be a case of David vs. Goliath, only thing time Goliath pounds David into the ground like a nail. But this case could be a catalyst for questions being raised about Apple's own business practices.
Let's be honest here, the most likely outcome for this case is that it never goes anywhere near trial and that Psystar will crumble under the weight of legal fees and close up shop. Apple is notorious for burying any opposition in paper.
But what if this case actually makes it to court? Well, in my opinion this is where things become interesting. In order to get that far I would imagine that Psystar will need help from its fairy godmother, but it's too early to rule out the fact that Psystar might just try to fight this (after all, a full two weeks after the suit was filed by Apple, Psystar still seems to be selling Open Computer and OpenServ systems that come pre-loaded with Mac OS X).
The most likely outcome of a trial is that Apple wins. That would put the brakes on Psystar from selling any more clones and, most likely, any settlement awarded would again pound the company into the ground. Remember too that Apple has asked that all Psystar systems sold with Mac OS on them should be recalled, so a judge could order that this should happen, which means that if you bought a Mac OS-based Open Computer or OpenServ, you could be ordered to hand it back so that it can go into a car crusher. A ruling like this would almost certainly mean that you're not going to see any Mac clones go on sale anywhere for a long time to come. Even if Apple doesn't sink Psystar and no systems are recalled, buyers are still going to be left out in the cold, with no warranty and no updates.
But even a win for Apple (and let me be clear, I'm not even going to bother entertaining any other outcome) could still result in fallout that might not be good for Apple. For example, questions could be raised over the validity of the End User License Agreement (EULA), and change in how this is seen could ripple far and wide through the tech industry (and, as Dana Blankenhorn mentioned, this could have implications for open source).
Another ill wind for Apple could come as a result of Psystar invoking the defense that Apple is behaving anti-competitively by limiting access to the Mac OS. While this would be a mammoth uphill battle for Psystar, and a plan that would most likely fail, it could cause trouble for Apple in other countries, in particular EU countries.