For the classical period in its strictest sense, that would be Mozart.
Considering the broader term, it's very hard to choose one. I'd say Beethoven, because he pioneered the path for the works yet to come in the 19th and even the 20th century, bacause his works both seem very accessible to the casual listener yet are still intensely rich and rewarding for the more analytic and/or experienced one.
Considering the broader term, it's very hard to choose one. I'd say Beethoven, because he pioneered the path for the works yet to come in the 19th and even the 20th century, bacause his works both seem very accessible to the casual listener yet are still intensely rich and rewarding for the more analytic and/or experienced one.