If you're looking for an easy to use, no-frills camera app then HD Camera for Android is a good choice.
The app has only three modes: camera, video, and panorama. You can change the white balance and exposure, as well as tag your location. It's one click to take a picture and pinch to zoom. The image quality is excellent and the flash works well, even in very low light.
HD Camera for Android has no advanced settings or image editing options, but it's simplicity makes it ideal for casual users.