Naturally, if a student knows that he's going to specialize in some field, he probably ought to take the cases most relevant to that field. Of course the first year classes — usually contracts, property, torts, criminal law, civil procedure, and (generally) constitutional law — are mostly mandatory, for good reason. You'd want to take some skills classes, depending on which ones the school is good at, and which seem likely to be relevant to your future specialization. And in my view the more writing classes you can take, the better.
But what other second-/third-year classes are important in nearly all areas of the law, so that a student should think several times before skipping them? Here's my list:
Remedies (injunctions, damages, restitution, etc., for the non-lawyer readers who are still reading this post).
Business associations (called "corporations" in some schools, though in theory "business associations" also covers partnerships and some other forms of organization).
Evidence (even if you're not going to be a litigator, it's helpful to understand things such as privileges, and various other rules about admissibility).
Any class taught by a professor with a last name of Volokh; doesn't matter what the first name is. Oh, wait, that means we'd have to grade more exams . . . .
What do you think? Thanks to reader Adam Levin for the pointer.