This appropriately named jewel of the Inner Sunset packs a visual punch on days (and evenings) when it's clear out. Sutro Tower, East Bay, Downtown, the Golden Gate Bridge, Marin, Ocean Beach, and others fill a stunning 360 degree view.
Also known as "Turtle Hill", this short steep hill is approximately a 15 minute walk from the 9th and Irving in the Inner Sunset - and it's typically windier and colder on top than below, be sure to bring a jacket.
And don't miss the amazing mosaic stairway on the west side!
Wikipedia: http://en.wikipedia.org/wiki/Grand_View_Park