When I was small, going to a movie always meant going downtown. We didn't do it often, but Main Street had at least four theaters and Five Points had one. The way I remember it, this all began to change with the opening of the Richland Mall Theaters (which deserve their own post). By the time I was in high school and college, the action had mostly left Main Street, with Dutch Square, Spring Valley, Richland Mall and Columbia Mall all having multiplexes (Columbia Mall effectively had two multiplexes).
The Jefferson Square Theater was the last theater downtown to play first-run major movies after the rest of the Main Street theaters had either switched to kung-fu, hard-R grindhouse or closed their doors entirely. "Jefferson Square" itself is still there, more or less at the end of the old Main Street shopping district. The theater building is still there too, though I don't know what's in it today. The last movie I remember seeing there was "Fame" in 1982. Even at the time, it was unusual to go downtown, and we had trouble parking (another part of what killed downtown theaters). I recall being impressed with the setup, which was on a larger scale than a typical multiplex. There was even a balcony, though it was closed at that time. We all enjoyed the movie (it seems to have fallen off the cultural radar now, but was quite a sensation at the time) and agreed that it was a nice place to see it, but we never went back, and I saw some time later that the theater had closed its doors.
I understand now that the Columbia Film Society is trying to move their Nikleodeon Theater from Main Street behind the State House to one of the shuttered theaters on Main in front of the State House. I don't believe that they are talking about Jefferson Square, but it will be nice to see a downtown theater of any sort again.
UPDATE 4 May 08: Added pictures of the current Jefferson Square courtyard.
UPDATE 12 September 2009: Added the Jefferson Square ad for "Two People" from the 15 April 1973 State paper.
UPDATE 21 April 2013 -- Commenter William sends in the picture below saying:
The current tenant DHHS leveled the floor by pumping truck loads of self leveling concrete. I am sending you a pic of the old projection room from about 2 weeks ago [circa 1 March 2013 -- Ted]. When I first went up there parts of the projectors were still there and you could see out the "windows". But as you can see in this pic they have been removed completely and windows blocked.