If we're limited to freeway driving, I-26 north out of Asheville takes the cake for me in the east. Of course out west there are many options.
One of the most boring is I-75 south of Macon. At least it's six lanes.
I-75 at the TN/KY state line (in TN actually) is interesting. It's one of the last segments finished and goes up, runs along a ridge at about 2,000 feet, then comes down (with a bit of a dip in the middle as it crosses to a second ridge). The WV Turnpike is nice in spots, as is the PA pike.