Sutro Project / Embarcadero
Running along the bay from AT&T Park up to Fisherman's Wharf, the Embarcadero provides a break from the city's steep inclinations. As such, it's widely enjoyed by locals and visitors on foot, bicycle, skateboard, rollerskate, etc... although traffic can be an issue both on the sidewalk and off.
Public art aficionados (and/or picnickers) might check out Vaillancourt Fountain!
The Ferry Building hosts a farmer's market on Tuesday and Saturday mornings in addition to a variety of local vendors. Red's Java House has a devout long-time following, excellent views and relatively low (formerly "rock bottom"..) prices.
Wikipedia: http://en.wikipedia.org/wiki/The_Embarcadero_(San_Francisco)
