Well, I'm stumped. That's because, I regret to say, viewfinders are going the way of the Dodd and Tri-X film. There aren't that many waterproof compact digitals out there, and all of them have LCD screens onlyno look-through viewfinder.
You could, for instance, purchase an Olympus Stylus 720 SW ($380; olympusamerica.com), a compact, waterproof (to ten feet), sturdy camera with 7.1-megapixel resolution. It also has such useful features as a 3x optical zoom (plus a 5x digital zoom, which I think is stupidit just crops the picture) and image stabilization. But, it doesn't have a viewfinder, only a 2.5" LCD screen.
The same situation holds true for the Pentax Optio W20 ($300; pentaximaging.com), which, like the Olympus, has a 3x zoom lens and 7-megapixel resolution.
Why no viewfinders? I think because so many people actually look at pictures on their camera, or show them to others, that camera makers have decided to beef up the LCD screens and do away with viewfinders. Which I think is a bad tradeoff. I'm always watching people trying awkwardly to frame pictures in the LCD screen, when in my humble opinion it's much easier to simply look through the viewfinder. I will go so far as to suggest that looking through a viewfinder also results in BETTER pictures, because the photographer is, at that moment, much more "in the picture," without all the distractions seen when the camera is held a foot or so from your eyeespecially if the viewfinder actually looks through the lens.
In the case of waterproof cameras, there may also be an issue of reducing any possible leakage points, something accomplished by eliminating viewfinders. For casual swimmers or scuba divers, it's also a bit easier to frame the photo with the LCD screen as opposed to squinting through the viewfinder and the diving mask.
So what to do? Personally, I'd just get a high-quality digital single-lens reflex camera like the Canon Digital Rebel XTi ($800 with an 18-55 mm lens; usa.cannon.com), a really spiffy little 10.1-megapixel camera, and use that for everyday shooting. When water is present, get a waterproof Aquapac case ($120; aquapac). That said, if you want to go really deep (say below 15 feet), you'll have to upgrade to a waterproof housing designed for scuba diving like those made by Ikelite (ikelite.com). These ingenious thick-wall plastic cases give you easy access to all the controls on your digital camera and are rated to go as low as 200 feet. But expect to spend at least the same amount on the housing as you did on the actual camera.