10sne1, I have a leather " pack" that my digital camera, extra batteries, extra flash cards, wallet and park tickets fit in just right. I make sure the camera is in and zipped for all the motion rides. For the water rides (especially Bluto's Bilge Rat Barges), I place the whole pack in the covered pockets they have on the ride. Several of the attractions, such as Jurassic Park River Ride, have lockers out front to put your stuff in. On that one last trip, I kept the pack with me and took pics through the first half of the ride, then stored the camera. It didn't get wet at all.
If your video camera is an old one like mine that is kind of large, I would suggest leaving it in a locker at the front of the park by Guest Relations until later in the day, then get it for a filming break from the rides.
(Note: Take a look at my webpage for some of the digital pics I took last year (see the Theme Park link). I haven't finished the page from my latest trip yet. Should be up sometime next week.)