If you look at Manhattan Beach, then choose Shade over Belamar for the location. It's a new trendy boutique hotel in downtown Manhattan Beach just a few blocks up from the beach/pier. Also, across the courtyard is Petros, which is an upscale Greek restaurant. Marriott overlooks a golf course.

Casa del Mar, Shutters, Viceroy, Loews, Le Merigot are all good upscale hotels in Santa Monica, but the driving distance is longer than what you want. More like 25-30 than 15-20.

Cheers.