Philadelphia is a good place to visit if you love arts, culture and history, is not if you like to see fancy things. Philly is no fancy. :-)

Some places to visit, in addition to those have already been mentioned:
1. South Street, like French Quarter in New Orleans. A must visit you like night life. Some good gay bars out there...
2. Rodin Museum. It has one of the best collections of Rodin's sculptures. It is just minutes away from Philadelphia Museum of Arts.
3. Museum of Arts. In Ben Franklin Parkway. One of the top five fine arts museums in the country.
4. Philadelphia Orchestra and the Kimmel Center. One of the most famous Orchestras in the world. Ticket not always available. You can get discount if you have student id...
5. Old City, tons of art galleries.


These are things I can come up right now. You do not need a car to visit the vanues inside the city. However if you would like to go to places like King of Prussia, Longwood Garden or Lancaster Country, you do need to get a car.

Have fun in Philly!