Not everything needs to be frozen in space. Sometimes action photos benefit from slowing down the shutter speed so things in motion blur better conveying their speed than a freeze frame would.
I shot this image with a slow shutter to allow the shark and moving water to blur creating a semi abstract frame. If you look closer you'll notice some spots in the image are still and in focus furthering the illusion of speed and power of the passing shark.
The image was shot at "Shark Reef" at the Mandalay Bay Resort in Las Vegas. Worth the price of admission as they control how many people are in the exhibit at one time so you actually get a little time and space to shoot what you want.
This image was processed from a RAW file with Adobe's CS5 and color corrected so it would look "right" when viewed.