Ringmir,
You'll enjoy your stay at the Serrano Hotel. My wife and I spent two nights there on our honeymoon a few years ago. Nice central location for walking around San Fran. They had a great happy hour with some good wines. To echo Alan's comment, the ferry trip across to Sausalito is worthwhile! If you have the time, drive up to Sonoma and spend a day or two at The Lodge at Sonoma, Renaissance Resort & Spa. We are heading back there this summer for our anniversary.
Cheers,
Shaun