For most of my life, "The Big T" as Taylor Street Pharmacy was known was the only 24-hour drugstore in Columbia. That said, it was far from the closest drugstore to my home, and a 24-hour drugstore is something you (hopefully) don't need that often, so I was probably only there a dozen or so times over the years.
The store, which was on Taylot Street above The Township and below Baptist Hospital, was unaffiliated with any chain (not unusual at the time), and I recall it as having rather a hodge-podge assortment of merchandise aside from the perscription department. I think one of the times I went when I was a kid, it impressed me as Lachicotte's at Pawleys Island set down in Columbia (though without the floats and fishing tackle). I do recall that they had a spinner rack of paperbacks, something I would always check in any store we visited, and some toys. I can't recall if they had a soda/short-order counter, but I would suspect that they did given the size of the store and that it was a standard drugstore fixture back in the day.
"The Big T" monicker was not just a common nickname for the place -- it was embraced by the store and used in their advertising, to effect, I think, since even people who didn't go there felt friendly towards the store.
In the end life became more difficult for unaffiliated drugstores, and most of that era (Campbell's, Cedar Terrace, Parkland Pharmacy..) are now gone. With the decline of downtown, the Taylor Street location became something of an obstacle as well, and the store finally sold out to CVS, who continue to operate it today, under a much reduced schedule (it apparently is not open on Sunday at all much less 24/7). It appears to me that apart from a revamp of the corner entrance to add CVS branded architecture, the main building is pretty much intact, at least from the outside.
UPDATE 14 March 2009: Added 1963 Yellow Pages ad.
UPDATE 31 March 2009: Added 1970 Yellow Pages ad.
UPDATE 10 March 2011 -- Some of the original Big T signage is visible during the current work on the building:
UPDATE 15 May 2011: Changed to closing date in the post title to 1994 based on commenter Andrew's research. (Oops, set it to 19994 the first time..)