First, note that the Vocations are intended as skeletons, to be fleshed out from these options to more complete archetypes. Suggestions are made in the notes for each Vocation on standard cyberpunk directions that each Vocation can easily take.
EXECUTIVE: This Mental Vocation forms the basis for any Corporate persona, ranging from the network administrator for a company to the persona supervising the company's postal room. Typically, executives will have received some assistance getting into their position, and never have an SEC of less than 4. In most cyberpunk games, this would cover nearly all corporate classes/occupations.
REPORTER: Reporters bring the news to the people, either by pursuing corruption wherever it may be found (rooting it out), or simply to sell papers. With the disintegration of society, this position has become much more dangerous than it was before.
MARINE: Marines are either currently in an armed force or have recently left. They are already trained in fighting. This makes a good base for a street fighter, a police officer, or any other combat-oriented occupation.
P.I.: The Private Investigator is often cut from the mold of hard-boiled dicks. This is a popular under-dog Vocation, as the authorities often work at odds with the PI.
HACKER: The Hacker is a Vocation encompassing Netrunning in all its forms, from early 90's terminal use to the far reaches of neural interfaces. This forms a basis for characters that, in other systems, might be called Netrunners, Crackers, Deckers, or others. Initial SEC is from around 2 to 5, although this can raise very quickly with some well-chosen hits.
DRIVER: Drivers run vehicles around, whether they are military, private security, or commercial. They are the best at it, and they are needed for any long-ranging mission.