Rule #1 of site mapsis that they do NOT fit within the confines of a computer monitor. Even a 27inch monster! Site maps have to make sense and be readable. That often meansthey have to be quite large. I always start with an A3 size and work fromthere. Site maps, especially on bigger projects involving large teams, are bestplaced on a wall. A large wall ideally.
Rule #2 of site maps is that if you own the site map you own the project.
Rule #3 of site maps is that if you have access to a plotter make the most of it!