Try San Clemente. The freeway is not far from the beach. Try Holiday Inn express off Pico or Best Western Casa Blanca on El Camino.
I'd suggest Newport Beach since it has the most beach area, both wide, white beaches as well as secluded coves with tide pools and cliffs that act as a backdrop. It also has two piers (with restaurants at the end of both of them) and the largest small yacht harbor in the world. It has the Fun Zone, harbor tour, the second oldest continually operating ferry in the U.S. and great restaurants and shopping.
If you give us an idea of the price range and type of accomodations you are looking for it would be easier to make a recommendation for a hotel.
For a digital guide to Newport Beach check: www.visitnewportbeach.com
Scroll down the the page and click on 'digital guide' on the right-hand side to view the entire guide.
Sounds like you will have kids, Carlsbad is about halfway between the two locations, has the LEGOLAND Resort (Three different parks) plus a nice Premium Outlet Center, and a nice beaches in the area.
Don't think you can go wrong with any of the places you mentioned or the ones that have been mentioned in the responses. Laguna is my favorite but San Clemente might be the most "low key" -- the others get very crowded in the height of summer (esp. Laguna due to the art festivals going on).
I've only spent about 3 hours in Laguna Beach travelling on a coach trip between San Diego and LAX airport but loved it.