Before I went to Myrtle Beach I had heard the recommendation that you should post on Twitter for tips on the location. I wrote a post asking what to do with a 7 and 11 year old (my nephews). The tips I got were to go to some indoor water park, Ripleys Aquarium and something else. The only thing I got to see, which I did with my 7 year old nephew was Ripley's Aquarium, and it was a nice place.
The whole aquarium is indoors, a plus when it's 32 degrees outside. The aquarium isn't terribly big, but it had a large selection of fish and exhibits, enough for a good hour to two for a family that isn't fish obsessed. We also did not see any of the presentations since the schedule didn't match ours. We also didn't buy any additional ticket items - like a movie. In addition to the fish tanks there was also an exhibit about babies and incubators included in the base ticket, which had little to do with fish, but was interesting anyway. It also had a couple funny photo spots, especially with a goofy kid like my nephew.
I'll admit I haven't been to all that many aquariums, the most recent was the Shark Reef at Mandalay Bay - this was smaller but just as nice. My sister often takes the kids to a couple different aquariums in NY and when they travel and she really liked this one and my nephew had fun too!