Where to go for a romantic 3-day getaway from SF Bay Area?

I'm planning a 3-day getaway weekend with my spouse for our 15th wedding anniversary in April. Willing to travel by car or plane (within limits of a 3 day trip). Looking for a place that is romantic and beautiful. Don't want to skimp on cost because I hope to be married 15 years only once! Having said that, I also do not want to be overly extravagant.