An architect is the one who does the job of planning of a project according to the requirements of the client. Assuming it is a typical building project the architect is responisible for the planning of the living area,viz. room sizes, corridors and other elemets according to the requirements and taste of the owner. Architect also responsible for the look and feel of the building, that is where they can show their talent to the max. and impress the client. He is also responsible for the right planning of secondary units such as plumbing/sanitary, mechanical and electrical equipments in the building. Last but not least he is also responsible to choose a cotractor to execute the work within the budget limitations of the owner.
Where as the structural engineer is the one appointed by the architect to design the structural elements such as decking, walls/columns, foundation etc. Upon the architect's request the structural engineer may also suggest the suitable and or ideal framing system for the building. Though the location of the structural elements is desided by the architect, in somecases they may not work out to be structurally safe and may have to be re configured and will be notified to the architect.
Finally, the arctitect is also responsible for coordination among all the groups involved in the building construction by means of periodical review meetings and its successful completion
As simple as furley's definition is, it is right on the money. Architecture, by its very nature, it totally concerned with the human relation to and response to a cumulation of "spaces" that allow activities to occur. Their job - beyond making it pretty, is to make sure people can function within the spaces and between the spaces.
While good architects focus on a balance between artistic expression and functionality, some architects get off balance and design nothing but foo-foo; artistic expression that is void of any useful or efficient space. These "bad" architects tend to make the building a "statement" instead of a habitat for humans. In other words, they let their ego get the best of them and ignore their clients true needs. While I haven't studied the layout and design fully, I would expect the triangular pyramid of glass at the Louvre in France a good example of a monument to someones self esteem.
Structural engineers, on the other hand, do exactly what furley states - don't let it fall down. Our systems and solutions do not always, or rarely, affect the client's activities and use of the building unless the project includes a lot of exposed structural elements. For most buildings, we structural folks are in the background, quietly supporting the architects dreams and (per ASCE's old motto) turning ideas into reality.
