We did Laguna beach last trip and are doing it again this trip.
I don't know about the other beaches, but Laguna was a perfect family beach. There are tide pools in the area, a playground for the kids, and even a little shop right off the beach that rents (at least I hope it still does!) boogie boards and beach toys. Last time we schlepped sandpails, etc, all the way from MO!
This trip I'm renting a car. If you do credit cards you can rent from Dollar for about $40 a day. There's a Dollar in a hotel just across from
Disneyland. I don't do credit cards so the best deal I could find was renting from National at the SNA. I still need to call to see if they will give us a ride to our hotel or if I need to pay for a shuttle. (UGH!)
However, if you want to impress the kiddies, you can get a limo. I did this last time. The company I used was Tony the Limo King. I got the name off the OC tourism site. My only warning is: get everything in writing. He ended up honoring the original price I was quoted, but only after trying to increase it substantially. He charged me $100 round-trip. I got to set the times.
There are tons of other limo agencies, and if you want a tour-type thing there is something called Woodies that takes you to the beach.
If you decide on Laguna, they have their own little magazine that you can request. It gives info on places to eat, shops, etc. My kids love the fact that there's an ice cream shop right across from the main beach.
The "downs" concerning Laguna: they have seaweed. Lots of it, lol! My kids didn't mind, and the views are unbelievable! We didn't even consider going to another beach this time!
As for parking: it's about 3 blocks up the hill in a lot. There is other parking, but it's metered and that is too big a pita for me to want to deal with!