Fort Point and the Golden Gate Bridge
photo credit: Thomas Sturm
Phenomenal views of the Golden Gate Bridge are available from Fort Point which is located just beneath the bridge. More info about this national historic site is here and also at the wikipedia article.
A great SF Chronicle article by Tom Stienstra: Marina Green to Fort Point
The fort is nearby other very scenic sites in San Francisco, e.g., Baker Beach, the Presidio, Crissy Field, Lands End, etc. A nice article about various sites to see terrific views of the bridge is Seven Places to Gaze at the Golden Gate Bridge.