I'm not a huge fan of water parks, too many stairs, and I don't like not having all of my stuff on me.  I also tend to frequently get snagged by the slide fittings on pretty much every slide, so I don't do many of the big drop slides.  My favorite water park would have to be either Typhoon Lagoon or Discovery Cove.
Typhoon Lagoon's wave pool is pretty epic, but I swear the bottom of the pools are made of death sandpaper.  I wonder exactly how much blood is in the water.