My favorite amusement park is Disneyland in Anaheim, CA. There are so many fun things you can do at the park, and it is all extremely family friendly. Even if you don't like crazy rollercoasters, there are lots of fun things you can do there.
Knott's Berry Farm has the best rides for people of all ages. Few are too scary and even the kiddie rides are thrilling for adults. The price of admission is reasonable. The park has lots of shady areas to escape the hot summer sun. California residents get a discount. The theme of the park is the Peanuts gang.
My favorite amusement park is Cedar Point. I think it so much because it is close to home, and there are the world's greatest roller coasters all in one place. The french fries are some of the best that I've ever had.