Raging Waters, The atmosphere is nice and stuff, but the travel channel channel really overrates it. All the big slides that have long lines are pretty overrated, but its actually got theming in the kids area, the lilypads are cool and can't be found in any other waterpark in socal. They also have the tube chute Robb and Elissa did at Sclitterbahn.
Hurricane Harbor, Its a really good little waterpark. Tornados cool and ther slide collection is pretty good!
Soak City Orange County is cool, Kind of like a more colorful Hurricane Harbor with less slides.
Soack City Palm Springs, Its a cool little small park. Worth a visit if you're ever in Palm Springs. Heres some photos of one of their rides. http://www.incrediblecoasters.com/SurfRiderRapidsPhotos.html
I'd suggest Raging Waters for your waterpark because its a really cool place. I'd actually suggest going to Hurricane Harbor for an hour on the day you go to SFMM. But most importantly, Have fun!