Not that I should speak with utmost authority but my best bet for fun driving in Georgia has to be the stretch of rt. 76 from Hiawassee all the way to the South Carolina border. The road is in good shape and the scenery is forested hills throughout interrupted only by the occasional post-card lake. But most importantly the road itself is good fun to drive the closer you get to South Carolina.

On the other hand the interstates are pretty monotonous, especially the drive from Macon to Savannah on 16. And speeding should be avoided on all of these because of the abundance of cops.