I have a good friend that is a native of Thomasville; my take on the town is that if you want to find a vestige of 'The Old South' in GA, you'll find it there. Thomasville is the unofficial capital of the 'Plantation' region of the state...it's surrounded by the large and elegant old hunting plantations that wealthy northerners maintained from the the late 19th century...some are still active, some are maintained as museums.
Besides that, I think T'ville is best known for it's annual Rose Festival.
www.downtownthomasville.com