My top 3 beaches in San Diego are:  

La Jolla Shores is my favorite when I’m with families, or friends with kids.  It’s just overall a family friendly beach.

Coronado Beach: I like the scenic views, very relaxed every time I go here, and having the Hotel del Coronado as a backdrop.

Torrey Pines State Beach: Less crowded with coastal cliff trails. Best for nature and hiking.

Get to the bottom of the Gliderport and look up.  There are beautiful cliffs, paragliders swooping around and hopefully a beautiful blue sky.
  The beach is beautiful and big depending on the tide.  Go one way and its a clothing optional and the other way is a great family friendly beach.