US276 - goes from Greenville/Traveler's Rest through Table Rock and Caesar's Head on towards Brevard, NC.
Very scenic. Quite windy too. Fun drive!
US178 - goes from SC to Rosman, NC. Not as trafficked as US276, but IMO a much nicer road for driving. 149 curves in roughly 17 miles (yup..we counted..hehe)
Just watch out for slow cars and bikers (oh and semis!)