Whilst it's beginning to show it's age in parts, t...

Whilst it's beginning to show it's age in parts, the experience is so vast that there's plenty for everyone to see and do.
The theme park isn't as great for younger kids (my 5 year old was too short for many rides), but it has a very good range for older kids (and adults!).
The animal park is respectful to the animals - if they don't want to be seen, you won't see them - but has so many enclosures that there'll always be something on show. Some even get you up close (I recommend the safari ride for that).
I highly recommend booking a two day ticket, so nothing needs to be rushed. Local hotels are in good supply and don't overcharge, so staying over isn't too hard on the pocket.