There are a lot of lovely beaches in this area, but for the most stunning scenery, Point Reyes National Seashore
would be my top pick. There are several dramatic and wild beaches there, and several locations where you can enjoy panoramic views of the coast.
Drakes Beach is one of the most popular spots at Point Reyes, with its white sandstone cliffs, easy accessibility, and Visitor Center. According to Google Maps directions, it takes exactly 2 hours to get there from San Francisco International Airport. The shortest route Google plotted was taking US 101 to Sir Francis Drake Blvd. (exit 450B).
The Point Reyes Lighthouse and Chimney Rock are popular places for taking in the view, but be aware that during whale watching season (late December to mid April) the road is closed and shuttles are operating on weekends and holidays, due to the popularity of whale-watching. And, since the Visitor Center at Drakes Beach is Stop 1 for the shuttle, that area will likely be crowded when the shuttle is running.
Another beach you might like to consider is Muir Beach (a 49 minute drive). This small sandy cove is located in the small town of Muir Beach. For panoramic views, you can head to Muir Beach Overlook, about a mile north of the beach on 101.
Heading south from the airport, Natural Bridges State Beach in Santa Cruz offers some lovely scenery. The drive takes 1 hour and 15 minutes. There's rocky coastline, with the much-photographed natural bridge (the last remaining arch), sandy beach, tidepools and hiking trails.
There are other San Franciso beaches that offer nice views, but these 3 are, I believe, the best.