In evaluating whether or not a clerkship will make you marketable, it is important to understand the differences between state and federal clerkships. These distinctions are examined below.
A. Federal Clerkships
Typically, the most prestigious clerkships have been those with federal judges. At top national law schools, students compete very aggressively for federal clerkships more so than they do for state judicial clerkships. Given the prestige of a federal clerkship, it can often make you marketable far beyond the geographic area where you are clerking.
At the federal level, the order of prestige of clerkships is typically (1) the Supreme Court, (2) circuit (appellate) clerkships, (3) federal district court (trial court) clerkships, and (4) clerkships with United States magistrates (who do a lot of the grunt work for federal district court judges). There are also several specialized courts (such as Federal Tax Court) that are of approximately the same prestige level as federal district court clerkships. For obvious reasons, clerking for the Chief Justice of the United States Supreme Court is generally considered the most prestigious clerkship there is. Similarly, a clerkship with a federal district judge in the Eastern District of New York is more prestigious than a clerkship with a federal district judge in Bay City, Michigan, for example, because there are far more people competing for clerkships in larger metro areas. Attorneys who clerk for the most prestigious judges are typically those whose marketability is likely to be increased as a result.
Most attorneys applying for federal clerkships apply to work either for federal district judges (district court clerkships) or for federal appellate judges. District court clerkships involve actual issues being litigated at the trial court level and typically have more in-court action. In a district court clerkship, you may see many of the same lawyers in court day in and day out. In a circuit court clerkship, you are likely to see the attorneys involved only when they present their appellate arguments in court. Appellate clerkships involve mainly research and writing about issues the trial court has already ruled upon and reviewing the District Court's errors. Appellate clerkships typically involve more arcane and novel issues of law than are typically litigated at the trial level. In an appellate clerkship, you are less likely to get to know the lawyers involved in the underlying litigation.