Islands of Adventure is one of the best theme parks we have been to. We do not typically go when it is peak season and this trip we did not visit on Thanksgiving Day, but we went every day the rest of the week and it was great. This time of year is warm enough not to need heavy coats and cool enough to be comfortable. Beware the water rides on cooler days though.
The park has areas that appeal to all ages from the Dr. Seuss land to The Hulk rollercoaster, which my husband describes as the most awesome rollercoaster he has been on. Later in the evenings the lines were shorter and some rides were ridden two times in a row because of the ease of going back through the line.
While smaller children would not be able to ride the more intense rides, there are shows that the entire family could go to and the little ones would be thrilled with everything in Whoville. We were there when all of the Christmas decorations were up in Whoville, and it was really a beautiful sight.
One of my daughter's favorite things to do was so simple and did not require a line. She loved going to see, hear, and talk to the talking fountain. We had to go there everyday just for the fun of it. I love all of the Disney Parks, Sea World, and Universal Studios, but if I had to pick a favorite I think it would be Islands of Adventure. Don't miss the Spiderman Ride. It's the BEST ride I've ever been on and I'm no spring chicken.