Plato's Grecian Cafe was tucked into a strip mall across the street from Dutch Square; today it's a Personnel company. I went there several times over the years, but it never really clicked for me. I always thought of it mainly as a pizza place, and though the pizza was fine, it was not in the running for Best Pizza in Columbia.
The last time I was there, they had some sort of live music. I can't recall if it were a pop band or some kind of Greek folk thing, but anyway that seemed to be where their focus was that night, and I found the table service really suffered for it. Since my inclination to stop was never strong, I never got around to going back after that, and didn't notice for a while that the place was gone.
UPDATE 2 March 2011: Add full street address and ad from the Feb 1990 Bellsouth Yellow Pages