In my room I have three posters of lighthouses. Each of these posters are similar to the Successories posters, in fact, they might actually be the real thing.
I picked lighthouses, because I wanted a theme and of the posters available at the time of purchase they were my favorite theme. I like the idea of lighthouses because of their purpose. They warn you of the coastline, light up the sea, and serve as landmarks to guide your path. They also make fun phallic symbols for when you're in the mood for sexual jokes.
Here's what they say --
Goals: Obstacles are those frightful things you see when you take your eyes off your goals.
Focus: All things are difficult before they are easy. Keep your mind on your goals and you will achieve them.
Vision: Effort and courage are not enough without purpose and direction.
That last one is my favorite. It is my favorite picture and my favorite anecdote of the three.
My other themes are "Van Gogh's night scenes" which is my current bathroom theme, and "Salvador Dali", whose art makes any meal comparatively more palatable, is my dining room theme.