If you have more than one camera (and a Mac), you need Cameras, a free preference pane app. It tracks all the cameras you plug into your Mac and lets you assign a custom behaviour for each one.
I've been using it for a couple of days and love it, since one behaviour does not fit all when it comes to all the cameras I use—when I plug in an iPhone it opens iPhoto to import photos, while my card reader triggers Image Capture, and the Flip opens up Finder. There's no reason you shouldn't download it: It's lightweight, free, and makes your life that much saner. [Flexibits via Lifehacker]