What takes the most space?

What takes up the most space in a map?

Depends what's in your map. If you have imports, usually them. Sometimes it's triggers, others its units (if you have bizarrely large numbers of Object Editor data).

From my maps, it seems it generally goes Imports > Triggers > Object Editor.

Map size also influences it, but that's usually how it goes in my maps.

Imports. By far and away in most maps. Unless you're doing something odd.

Sound is very large. Then textures. Then models.