I am an amusement park junkie and I have no kids. I frequently go to parks either alone or with adult friends that also don't have kids. I love Disneyland and Seaworld, if that helps.
I looked at the ticket price yesterday and was shocked that it was as much as Disneyland. I couldn't believe it.
Walt Disney World's Magic Kingdom
Disney's Animal Kingdom
Disney's Hollywood Studios
Disney California Adventure
Universal's Islands of Adventure
Universal Studios Florida
Universal Studios Hollywood