SeaWorld and Busch Gardens are my two favorite theme parks. I live close to Busch Gardens but visit SeaWorld several times a year.
I buy the 2 year pass for both parks. This runs around $200. You get free entrance, parking, and lots of discounts.
SeaWorld has great shows, rides, as well as the fish, dolphins, penguins, sea lions, polar bears, etc.
There are great places to eat too. You can also get 2 free samples of beer per day if you are 21 or over.
They often have buy one day, get a second day free.
If you are staying in the Orlando/Kissimmee area then you must visit. It is off International Drive and you can get directions from their website.