It depends on what you are looking for. If you are thinking Florida -- fine white sand and warm water -- none of them. The water will be VERY COLD. Wear a wetsuit.
If you want to lie on the sand and soak up sun, your best bet might be the inland (harbor side) beach off Belmot Shores. It will be the most protected from winds. You can also walk across Pacific Coast Highway to the ocean beach of Belmont Shores and enjoy both. Shopping and restaraunts are along 2nd street. If you do not like waves, Long Beach or Belmont shores are good because there is a breakwater offshore that shelters these beaches.
If you want waves, you have to go to Seal Beach or further south to Sunset Beach and/or Huntington Beach. Seal Beach has nice shops and restaurants along Seal Beach Blvd and the walk down the pier is nice. There is a a Rubys restaurant at the end of the pier which we enjoy. Huntington Beach has a large revitalized area near the pier also.
Depending on where you are staying, you may also want to consider Manhattan Beach, Hermosa Beach or Redondo Beach (north from the cruise ship harbors). I haven't beeen there enough to give much information on them.
You're not likely to see seals on any beaches.
Weather-wise, fall is usually the least foggy time of year, but Halloween can be turning back to fog season.