While in law school, I planned to go into corporate practice and took every tax, securities law and corporate entity course I could get my hands on. Sometimes I chose a course knowing that it would likely cost me, GPA-wise. While other students were taking courses like "Sports Law", I took the most difficult challenging courses I could find.
Ironically, my two primary practice areas today are intellectual property and employment law. I took neither in law school. You might ask whether I regret not taking them; or alternatively, whether I regret spending so much time and energy on courses I'm not really using today. Even funnier is that fact that today I actually do practice Sports Law and work with all of the major professional sports leagues. The truth is, that I benefitted from taking the courses I took, regardless of whether I ever actually used the substantive law.
You should certainly do some planning as you think about courses. But at the same time, understand that plans change. The great thing about law school is that after your first year, many if not all courses are electives (I went to Vanderbilt, and most everything I took after that first year was at my election). So, you have a wonderful opportunity to explore and take courses that interest you.
Further, if you plan to practice law long term, it is likely that at some point in your career, you will run into areas of the law where familiarity will be of benefit. So the good news is that virtually any course you take will likely be of benefit in practice.
I think the most important thing is to graduate from law school with a set of skills that will enable you to learn new areas of the law. In practice, you will likely be exposed on a frequent basis to new laws and regulations, but also to new clients, industries and businesses. So, the important thing to learn in law school is how to learn. As a result, your goal for a legal education should be to learn, think, write and act like a lawyer. Some of these skills can be taught in the classroom; others are picked up on the job.
At the same time, you should consider that your bar authorities, by virtue of their exam, expect a minimum level of competency in certain subject areas, in order to earn the right to practice law. Some of these subjects, such as Uniform Commercial Code courses like Secured Transactions aren't much fun and many students shy away from them. However, trying to learn any subject, especially a difficult one, quickly for a bar exam makes for a stressful two month bar preparation experience. So, you should consider taking courses that are "bar exam" courses, as well as courses that will enhance your legal skill set.
You may also want to talk with lawyers- ask them which courses they wished they had taken in law school but didn't.
Finally, its axiomatic in law school that "you don't take the course, you take the professor." And I think there is a lot of truth to the axiom. A good professor can make a bad course an absolutely enriching and enthralling experience. And vice-versa. Talk to students ahead of you. Ask to review the professor ratings, if they are available. Consider talking with the professor before you sign up. Ask him or her what their objective for the course is. Do some due diligence.
But with most law schools, I think it would be difficult to make a bad choice in any course. They will all benefit you in some way. So, relax and enjoy the experience.
At the same time, you are spending a great deal of money on your legal education. And yet many students spend more time considering the ripeness of a cantaloupe in their local supermarket than they do on their course decisions. Take some time to consider courses. It will make your law school experience infinitely richer.
Best wishes in your legal education.