Whatever the type of event or number of participants, the options are rows or theatre style, classroom style, U-shape, T-shape, blocks of tables or cabaret style. What is suitable for a small meeting is not necessarily right for a major convention. Some make optimum use of the space, others encourage interaction, and others enable participants to make notes or participate.
With regard to catering, there are also banqueting style and standing reception/cocktail party.
Click here for diagrams of variousused for official auditorium/room layouts.