There are so few "rides" it will be pretty hard to miss any of them! See the Shamu show and if you're staing all day, see the "night time" shows and Cirque if you already haven't seen it before.
We went to SeaWorld two weeks ago. I highly recommend taking the time and feeding the BatRays. My eight yr old daughter completely loved it and we had to go back to it alot. She loved feeding the dolphins and petting them as well. All the shows are great too. I loved the Altantis ride the most. Take the time to walk thru everything and experience it all. Have fun.
Feed the rays. Seriously, they're like huge Portabello mushrooms that suck frozen squid out of your hand. And go down and see the eels while you're in that area. You can also feed (and pet) the dolphins, and feed (but not pet) the sea lions in their areas. Just don't let the seagulls steal the fish from the tray, or from your hand.
And besides the simulator ride at the beginning, the Wild Arctic exhibit also has polar bears, beluga whales, walruses, etc. in a simulated arctic base that has walls covered with ice. Especially nice on a hot day, as is the penguin exhibit.
The sky tower and sky buckets (or whatever they call them) give you a great view of the area, and are nicely relaxing after all of the madness of the crowds.
And for food, I like the shipwreck restaurant (again, blanking on the name) right next to the Shipwreck Rapids ride. The teriyaki salmon's really good, and it's such a great themed area. A but pricey, but so's everything there.