Alcohol 120% is my image maker of choice, although it costs 49.95USD. Daemon Tools has the same functionality, but it's a bit harder to use to make straight images. In the case of making game images, Daemon Tools actually emulates copy protection when an image is mounted, rather than writing the correct sectors into th image itself. If you're not talking about game/copy-protected CD images, then... just use Nero's NRG format if that's what you use to burn.