Columbia [1] is a fun town with plenty of nightlife, especially when University of South Carolina [2] is in session. In addition to its cultural offerings, there are two main areas to remember for entertainment, dining, and shopping: Five Points, the intersection of Harden, Green, and Saluda; and the Vista (sometimes called the Congaree Vista), a more recently restored area closer to downtown amidst the old mill buildings.
Links:
[1] http://www.moon.com/destinations/south-carolina/columbia-and-the-midlands/columbia
[2] http://www.moon.com/destinations/south-carolina/columbia-and-the-midlands/columbia/sights/university-south-carolina