The Walt Disney World Resort located in Lake Buena Vista, Florida, near Orlando, is the flagship of Disney's worldwide theme park empire. It is, by far, the most popular theme park resort in the world. Some visitors describe it as a place of magic, wonder, and fantasy; others speak of fun, excitement, and relaxation; and still others complain of crowds, artifice, and unrelenting tackiness. As with most things, the essence of Walt Disney World lies near the intersection of those three views.
There used to be some times of year when the parks were relatively deserted, but not so much anymore. Now they just vary from "moderately busy" to "completely insane". Still, deciding when to go remains a game of trade-offs: you must decide whether to favor lower crowds or longer park hours, and decide whether you prefer scorching days or chilly nights.
The peak periods for attendance are late December, mid-June to mid-August, and mid-February to mid-April. Why? That's when kids are on break from school. If you have kids, you may have no choice but to go during these peak times. The bad news is that you'll be packed like sardines next to 50,000 of your new closest friends, you'll wait two hours to go on rides like Splash Mountain and Soarin', and you'll be paying a premium for the privilege. In the summer, you also get to listen to the kids complain about the heat. On the bright side, though, you'll have plenty of company, the parks are guaranteed to be open late, and as many rides as possible will be up and running.