I saw this posted in the SoCal and NorCal forums. I think we've got the best roads in the country. Here's a couple - post yours!
US 421 "The Snake" - Mountain City, TN to South Holston Lake. 14 miles.
US 221 - Blowing Rock, NC to Linville, NC. 18 miles.
Shull's Mill Road - Boone, NC to Blowing Rock, NC. 7 miles.