The new Sony Alpha 330 and Sony Alpha 380 have a nice specificity that is worth mentionning separately: A special autofocus (AF) system designed to maintain maximum performance even in LiveView mode.
Usually, the LiveView mode is done merely by moving the reflex mirror up. The image is then projected onto the single image sensor of the phot camera (like it is done in the point and shoot cameras). But in this case, the little AF sensor is no longer able to work. The main image sensor is used. Instead of the best phase detection algorithms, the camera must used a less powerful micro-contrast detection approach.
Sony decided to opt for another solution, more innovative. The AF sensor (4) is always kept in full operation (the reflex mirror (3) is not moved up). Instead, when going in LiveView mode, a small viewfinder mirror (1) is used to direct the view either toward the eye cup, or toward a LiveView video sensor (2). Everything is visible on the Flash animation below.
Kudos to the Sony engineers.