This list of roles is being discussed and refined here - http://groups.drupal.org/node/67763
Note regarding context: we recognize on many projects a person might take on some or even all of these roles. We're using the redesign of Drupal.org as the context for the associated roles. It's a larger project, therefore with greater differentiation in the roles. Therefore, helping to guide the discussion.
Note regarding tasks: the descriptions in the roles mentioned here are not exhaustive. We're mainly focusing on the names of the roles. The descriptions are for clarification.
System Architect
This person sets up and maintains the system and infrastructure on which Drupal is deployed. They can manage the migration of data and content. They also install and maintain access to the site and version control. An example: http://groups.drupal.org/node/66638Developer
This person can code custom modules according to coding standards and best practices. They can test the quality and security of the code they write. An example: http://groups.drupal.org/node/66643Themer, Front-end developer
This person can interpret visual designs into code. They are experienced with the complementary skills of HTML CSS and JavaScript. They can use theme functions and may be able to create custom modules to implement hooks to create displays they need.Site Builder
This person installs and configures modules to create site features. They will be knowledgeable about theming and development, but will mostly use the Drupal through use of the administrative interface.Content Editor & Manager
This person manages content and users on a Drupal site. They may not know many of the advanced functionality of the Drupal Administrative interface.Design, UX
This person may not know HTML, CSS or JavaScript. They specialize in visual design but with an understanding of the capabilities of Drupal which help them create designs which can be understood and implemented with their teamProject Manager/Planner
This person negotiates project plans with clients based on the understanding of the capabilities of Drupal. They understand best practices and can communicate client needs in the language of Drupal to the team.