Positions This is by no means a comprehensive list of positions, and you should feel free to put forward your own.
Alien Technology Specialist (2) - has experience in the use of alien technology, either generally, or focused on one particular species' technology (for example, the Ancients or Wraith).
Anthropologist - specializes in the study of the origin, the behaviour, and the physical, social and cultural development of people.
Archaeologist - an anthropologist who studies prehistoric societies.
Astrophysicist (2) - specializes in the physics of space and celestial bodies. Astrophysicists generally have some level of expertise in the workings of the Stargate system.
Biologist - a scientist specializing in the study of living organisms.
Biomechanical Engineer (1) - someone who studies and tries to augment interactions between the organic and the inorganic (such as with nanites and cyborgs).
Bodyguard (1) - someone whose job it is to protect someone else.
Botanist - a scientist specializing in the study of plant life.
Chaplain - A member of the clergy (such as a priest, minister or rabbi), responsible for the spiritual wellbeing of personnel.
Chemist - a scientist specializing in the composition of matter and its small-scale properties such as reaction rates and other chemical properties.
Combat Specialist (2) - usually, though not exclusively, a member of the military. Specializes in combat techniques and strategies.
Custodian/Janitor (1) - responsible for the cleaning and general maintenance of the inhabited sections of Atlantis.
Demolitions Specialist - an expert in the use of explosives.
Diplomat - responsible for establishing peaceful contact and negotiating agreements with the people of other worlds.
Engineer - a scientist who uses creativity, technology and scientific knowledge to solve practical problems.
Food Services Staff - responsible for maintaining the mess and providing meals for personnel.
Geologist (1) - a scientist who studies the origin, history and structure of the solid matter of the Earth and other planets.
Intelligence Officer (1) - responsible for collecting, compiling and analysing intelligence through both conventional and covert means.
I.T. Specialist - specializes in computer technology, involved with studying the vast Ancient computer networks in Atlantis.
Journalist/Documentarian - one of the select few historians or members of the press who have been cleared to document the expedition, in preparation for a time when the Stargate Program might be declassified.
Liaison (2) - a representative of a particular country, organizations, planet or alien race.
Linguist - a specialist in the area of languages.
Mortuary Staff (1) - from coroners to technicians, the morgue staff are involved with the recovery, identification and burial (or transportation back to Earth) of deceased personnel.
Nurse - involved with maintaining the physical wellbeing of personnel.
Pharmacist - manages the acquisition, storing and dispensing of drugs and medicines.
Physician (3) - a medical doctor, charged with maintaining the physical wellbeing of personnel.
Physicist (1) - a scientist who studies physics, from sub-atomic particles to the behaviour of the material of the universe.
Pilot (2) - an aviator, trained to fly aircraft and likely involved with the operation and study of alien air and spacecraft.
Psychologist - specializes in the study of the human mind. The psychologist is responsible for the emotional wellbeing of the expedition members.
Scientist (1) - someone whose scientific interests are varied enough not to be considered a specialist in anything.
Security Personnel - responsible for the protection of Atlantis personnel, whether on the base or off-world.
Sniper - an expert marksman; specializes in shooting from a concealed position or at long ranges.
Special Ops (2) - highly-trained, specialized military personnel, typically a member of a special forces unit such as the Navy SEALs or the SAS.
Strategist - an expert in strategy, they plan, scheme and provide new possibilities for courses of action.
Supernatural Specialist - an expert in areas relating to magic, demonology and other supernatural entities and occurrences.
Technician - similar to an engineer, but has a more practical, hands-on understanding of their field.
Traveller (1) - someone whose main purpose in life is to travel from place to place, never settling in one for long.