Although I've been to 18 facilities on the ZooChat forum list, some of them are museums and others are permanently closed. So, I'll pick out my top ten from these even though they aren't all technically zoos.
1. Los Angeles Zoo (Despite all of its problems, I've visited since the 1980s and have had many good experiences there.)
2. Marineland of the Pacific (This facility closed down in 1987, but it was wonderful with an assortment of animal shows and an amazing oceanarium. I also got to pet dolphins!)
3. Lion Country Safari in Irvine, California (This drive-through safari has been closed since 1984 so my memories are vague. However, it did leave a very positive impression on me at the time and it was quite an adventure for a little kid!)
4. Oregon Zoo (I haven't been there since 2003, but it was my home zoo for many years.)
5. Natural History Museum of Los Angeles County (This is one of those non-zoos on the list, but it does have fantastic dioramas of taxidermized animals and dinosaur fossils).
6. SeaWorld San Diego (This is another place I haven't visited for decades, but I greatly enjoyed the Shamu and dolphin shows along with the penguin and shark exhibits.)
7. San Diego Zoo Safari Park (When I visited, this was known as the San Diego Wild Animal Park and I rode on the now-defunct Wgasa Bush Line monorail.)
8. Aquarium of the Pacific (I visited the year it opened in 1998. When I heard the aquarium had a shark touch tank, I somehow envisioned petting great white sharks and thought that would be very dangerous. Imagine my relief when I saw the small carpet sharks in the touch pool!)
9. Santa Ana Zoo (I've recently become a member there and appreciate the investment the zoo has made in the Children's Zoo farm area.)
10. Cabrillo Marine Aquarium (I first visited there on a school field trip when it was called the Cabrillo Marine Museum. It has expanded a lot over the years and is located within walking distance of the beautiful Cabrillo Beach.)