Neat idea for a thread! I've heard good things about the Wild Arctic Up-Close Tour.
I myself have taken three of the tours at SeaWorld: Behind-the-Scenes Tour, Beluga Interaction Program, and the Marine Mammal Keeper Experience. I'm not going to give away too much information
, but I'll post a few things about each one.
What I like most about the Behind-the-Scenes Tour is the focus on animal care and rescue. You come out of that tour really appreciating the work that SW does for the animals. Plus you get to touch a shark and a penguin.
The Beluga Interaction Program was neat. You do get very up close with beluga whales, and you'll be with an animal care specialist during the beluga whale interaction. One thing I underestimated was how FREEZING the water was!
EDIT: IIRC, the water is 50-52 degrees! My hands were in pain from touching the water. But hey, you're up close with beluga whales! There are professional photographers capturing the whole interaction, and I did buy the photo CD because I really liked how the pictures came out.
And of course, the MMKE. LOVED that one. You basically follow an animal care specialist for 8-ish hours and get up close encounters with many of the marine mammals in the park. I highly recommend this one if you are interested in a career working with animals someday. Very worth it.