Going out at night and having to deal with public trasportation can be a pain. Most bus and train routes stop running by midnight. Depending on where you live, you may not even try going out unless you have a ride.
SEPTA just announced a series of improvements, which include increasing late night transportation. If done right this could be huge for the nightlife scene, which is pretty weak considering we are one of the largest cities in America. Let's keep our fingers crossed!