California highway 1 south out of Legget (from 101). The first 15 miles or so are fantastic.
There's a stretch of 191 in Arizona that's amazing, I think it might be Clifton to Alpine but can't remember for sure. I remember looking at the map and thinking, "It's only 120 miles, I can get there before dark," then seeing the first few 10mph curve warning signs and thinking, "Well... I'll just have to go REALLY fast on the straight parts..." It was a hell-ride, but it was fun.
129 in Tennessee (the Dragon) is well known, for good reason!
It's hard to find really good roads near where I live (Seattle). My favorite so far is about a 2 hour drive away. From Randle,WA on highway 12 (east of I5) go south on FR-25 for 20 miles, then right on FR-99. 99 up to Windy Ridge is just perfect for the Elise: 2nd gear the whole way, maybe an occasional shift to third if you're particularly daring, curvy with lots of 15 mph switchbacks, good pavement, not much traffic during the week. I used to take FR-26 instead of 25 on my motorcycles but in the Elise it's just no fun -- only one lane wide and frequent washouts. Oh yeah, it has some great scenery too.