For roads to drive my favourite is Route 1, from San Francisco (leave 101 at Sausalito), all the way up to Jenner (on the Russian River). I am sure it is equally beautiful further north, but that is as far as I got. Goes all the way to Leggett, where it joins the 101 again.
Oh yes, there are some lovely sections there. Stayed a couple of nights at Mendocino. Beautiful place.
Route 1 South from SF is not too shabby either, but a different kind of scenery, more barren and remote.