Any good solution must be complete, and cover the entire domain of issues well. Solving "The Napster Problem", in isolation from anything else, is not a solution at all; any decision made in isolation in that case will only create more loopholes and special cases that others may find ways to use to their advantage. For example, there was once a bill before Congress that would specifically allowed people to do what MP3.com wanted to do with its "beaming service"... are they ready to guarantee the same rights for all other media as well? Is that law ready for the case when some company allows people to scan their VCR tapes somehow, beam confirmation to the company's servers that they own a legal copy of the movie, and allow people to download the digital video version? If not, why not? Movies are just like songs in most of the important respects; the only reason it's not already happening is that movies are large. (This also serves as a good example of a non-robust solution as well; what little virtue the bill had when it was proposed will only diminish over time.)
I emphasize that is only a particular example. There are tens or hundreds that could plausibly generated. The solution must be complete; it can't just deal with music, but ignore movies. It can't deal with movies and ignore computer games. It can't deal with books, but ignore websites. Far too many little solutions to little problems have been proposed, but since each interact in unpredictable ways, they can never solve more problems then they generate.
This requirement basically knocks the court systems out of the running. Courts can only properly rule on cases that are before them, and they basically lack the ability to create coherent systems of law. Congress is much better at that, so we must expect a legislative solution. It should also be clear that the legislative branch in the US is currently writing laws that are no more coherent then the court system. If it isn't clear to you yet, contrast a law like the DMCA with the general framework proposed in this essay and you'll see what I mean. In fact, Congress is several steps behind the courts, as the courts have had to deal with actual conflicts and resolve them somehow, while Congress was able to just ignore the problem, or view the issues through only one side's point of view.