Hi cdvictorin,
Congratulations on your trip. I see that you're in Yorba Linda. If you've been to
Disneyland, I think you'll find many of the attractions in the Magic Kingdom similar to that park. The Magic Kingdom is larger, and feels much bigger, IMHO, but if there's one park that "is like" Disneyland, it's the Magic Kingdom.
I'd say that Epcot and the Animal Kingdom are much different than other theme parks, however. Epcot is roughly twice the size of the Magic Kingdom, I believe, and therefore something like four times the size of Disneyland. The park is adult-oriented and diverse, and its general theme is something like "the promise of the future." Even when some of its presentations are slightly outdated (e.g., parts of Spaceship Earth), it's interesting to be able to step back and see how far technology has progressed. Today's cheap cell phones would have been wonderous things 30 years ago, for example, and we can always consider how the heck we can use new technologies to improve people's lives.
Also, Epcot's rides are designed for huge crowds. As you can see from the opinions already expressed, many folks (including me) consider it the best of Disney's theme parks. World Showcase is not to be missed.
The Animal Kingdom, while having fewer attractions than any other park, also invites contemplation. While most theme park guests are conditioned to run from attraction to attraction, the animals are the real stars here. If you have the time to visit, mixing in a few headliner attractions with the animal exhibits will greatly increase your satisfaction with the park.
If you've been to Disneyland, therefore, my two recommendations would be Epcot and the Animal Kingdom. If you've not been to Disneyland, I'd say the Magic Kingdom and Epcot.
Thanks to everyone who recommended the Unofficial Guide.
Sincerely,
Len