All interior decoration and furnishings set a scene, the stage for life events. It is the background against which you, your friends and family will live, so it is vitally important that you feel it is an environment in which you can be yourself. This is why architecture, furnishings and colour matter so very much.
My advice is: set yourself a brief, do the research, get your eye in, and then choose from your heart. Of course, you and your partner might not always agree on details–however, if you are thinking of setting up a home together you will at least share the same fundamental principles of homemaking. Teenagers think everything precious to you is rubbish, their opinions are very important–but for their rooms, not yours.