Coronado is pretty, but it's way out of the way for what it is.
I still prefer Mission Beach which is across the street from Mission Bay, for a first time visit there is more bang for the buck.
For a non tourist beach yes La Jolla is georgous, but so is Sunset Cliffs (just down the road from Mission Beach)
I don't really care for OB (a boardwalks walk from Mission) but I HATE PB (Ghetto head shops and and homeless hangouts)
**edit: can anyone tell me why the first pic I post in a thread only comes up as a link, but the rest post fine?