I looooove amusement parks. Growing up in LA I went to Six Flags Magic Mountain most often because they offered "twickets" which let you come back for free or a couple bucks. I also LOVE roller coasters!
Disneyland and Universal Studios were also always a blast.
Now I can't wait to go to Harry Potter World! Alas that probably won't happen until the kids are a little bit older.
Which amusement parks are your favorite?