Do you want shiny (silk) or not shiny (matt)
If you have anything but perfectly flat walls silk will show al the imperfections too.
You wouldn't use silk emulsion on door and skirting surely. You'd use gloss.Matt for the walls and ceiling, silk for the door/window frames, and skirting board.
You wouldn't use silk emulsion on door and skirting surely. You'd use gloss.
Edit: Oh, +1 Matt