The women of Sports Illustrated or Olympic gold medalists will probably adorn your college dorm room walls if you're an athlete or rooming with athletes. In American culture, the term "jock" has become synonymous with someone who is extremely attractive and popular amongst his peers. Since jocks are typically focused on sports and athleticism, hanging pictures of your favorite sports teams or players is probably not a bad idea. Hanging pornographic or overly sexual pictures may be against dorm rules. Make sure you're aware of what is acceptable so you don't break any rules for displaying objectionable material.
If you're more into academia than athletics, chances are you fall into the category of a scholar. In this case, you may want to orient your dorm room pictures to focus on those individuals who fascinate you within various subject areas. If you're a political science major, you may have a leaning towards specific presidents or members of government. Medical students will have doctors they admire and law students will have attorneys that impress them. Math and science majors may find the work of Dutch graphic artist M.C. Escher fascinating, as he employs the use of geometric distortions and polyhedra in several of his works.
Artistic college students have a wide range of picture choices depending on their preference for music, the performing or visual arts. The works of Dali, Frida Kahlo and Pablo Picasso are renowned worldwide, and several reproductive prints are available online. The same holds true for Broadway productions like "Phantom of the Opera," "Les Miserables," "Cats" and "Rent." Musicians who specialize in classical music may hang pictures of artists like Yo-Yo Ma or orchestras like the London Philharmonic Orchestra. Pictures of rap and pop artists abound aplenty on the Internet and in local music stores.
If your personality or those of your roommates are more rebellious in nature, then decorating your dorm room walls with outspoken figures, slogans and artwork should come naturally. Revolutionaries like Che Guevara, Martin Luther King Jr., Ghandi and Malcolm X all fought for equality. Their posters are available in significant quantities online. You can also find several posters with slogans like "Fight the Power" and "Power to the People" online. Whatever your cause, there's probably a picture to support it. If there's not, you can always create one.