As "Believe" is a bit too...sentimental...for me, I love Shamu Rocks. It's a much more upbeat atmosphere, more "fun" than "beautiful" (which is what I think they're going for with Believe.
But hey, I'm an incurable cynic. If you like Hallmark commercials, you'll love Believe, so check them both out! Shamu Rocks is usually right before the fireworks, so it's a nice way to kill time before that final show either way.