Sea World has enough to keep a person busy for two days if you see all the shows, so consider buying a 2-day pass. Most daytime shows were excellent, with Pets Rule! being the exception. (There was little that surprised the audience.) Dolphin Discovery is probably the best show, although Shamu Adventure is considered the big event and is certainly worth your time. Pirates 4-D is fun--if you don't mind getting wet.
The schedule for night shows varies, so plan your visit accordingly if you want to see some of them. Except for Shamu's House of Douse, they have a more carnival-like feel to them than the daytime shows.
The opportunities to touch and feed animals including dolphins, batrays, and starfish are worth their weight in gold. SeaWorld evidently knows that because 4 miniscule fish for the dolphins cost $3.50, and they tend to be stolen out of one's hand by seagulls.
The penguin exhibit, manatee rescue, and shark tunnel are among the best sites in the park and deserve second or third viewings, or just a nice long rest on a seat in front of one of the tanks.
Most of the smaller aquariums are lovely and well designed, although most don't contain all the fish listed on their signs, and many contain unidentified fish.
Consider taking the behind-the-scenes tour, especially if Melissa is your guide. You'll see some sea mammals and turtles who are enjoying a day off or being nursed back to health. You'll also have the opportunity to pet a baby shark.
The rides may be the least interesting attractions in the park. Shipwreck Rapids requires a warm day to be remotely enjoyable, and enemies, friends, and strangers alike can buy the opportunity to squirt you with a water cannon when you are at your most vunerable on the raft. The Wild Arctic hydraulic ride offers you the option of motion-filled or motion-free transportation to the arctic, followed by a wonderful opportunity to view wildlife native to the area. Unless you have a cast-iron stomach, take the motion-free ride and then enjoying viewing the animals.