Often referred to as the most luxurious hotel in the city, The St. Regis San Francisco is surprisingly hip considering the staid reputation of the brand. Located close to the gay nightlife of SoMa, it's also just a nine-minute walk from the shops and restaurants of Union Square. Rooms are tastefully decorated with exotic woods and rainfall showers, and there's a 9,000-square foot high-end spa and fitness center with lap pool on-site.