The best road in Northern California is Wentworth Springs Road:
http://www.motorcycleroads.com/75/91...acerville.html
I've been on pretty much all the "driving" roads in Norcal and this is by far the most worth going out of your way to drive on.
Highway 36 is also really interesting, but thats a looong road with a few very interesting (very different) sections.
There are a lot of "tourist" driving roads here, like Highway 1 and 49, but they are too busy and less interesting as roads themselves.