I've lived here my whole life (well except for undergrad) so I thought I would add some more about the city.
Columbia is most definitely NOT a college town. It's just your average American city with some malls and different areas of the city. Down near USC there is 5 Points which is for the college crowd with lots of bars, places to eat, and little boutiques and stores. There's also the Vista which is closer to the State House and "downtown" (office buildings, government offices, public library, Finlay Park) and it's a little more expensive with nicer restaurants and more upscale bars.
No professional sports teams because most people are more interested in USC sports and football season is big with 80,000 people in the stadium. Night life is pretty fun, I mean it's not Athens but there are plenty of bars with different groups of people so if you're not fratty, there are places for you to hang out. There's a river near the Riverbanks Zoo (ha, get it?) that a lot of people go to and there's also Lake Murray, which is about 20-30 minutes from campus. Various museums, lots of movie theaters, etc.
Everyone is nice and friendly but the weather is HORRIBLE in the summer. Muggy, hot, humid, sick. Honestly one of the hottest places I've ever been because there's no breeze from any kind of water or anything. Just writing about it makes me uncomfortable haha but very mild winters, leaves change color in the fall, flowers bloom in spring, etc so you'll get four seasons. The weather is notoriously crazy though, sometimes it'll be in the 70s in the winter and then two days later it'll be 45. It might snow once a year and that will be like 1-2 inches and the whole city shuts down, which is awesome.
The best thing about Columbia is that it's right in the middle of the state so it's close to everything else SC has to offer. 2-4 hours from the beach, depending on which one you go to. 1 1/2 - 2 hours from Charleston, 3 hours from the mountains, 4 hours from Atlanta, 90 minutes from Charlotte, 5 hours from Jacksonville.
You will definitely need a car if you live in Columbia. There's a bus system but it sucks.