That is exactly what I was hoping for when I saw the optical and analog audio outputs on the TV (Samsung LN-3251D), but I don't think it allows for you to switch the TV speakers to the optical out. In fact, if you want to use a receiver (or any type of external speakers) by way of the audio outputs, you must turn the volume down on the TV itself. Otherwise, sound comes from the TV speakers as well as the external speakers and, more importantly, the TV volume controls only the TV's internal speakers.
As I mentioned previously, I have an old Sony DAV-X1 (HTIB), which is currently connected to the optical out and it works properly. The cable box and Apple TV are connected to the TV by HDMI and then I run a TOSLINK cable from the TV's optical out to the DAV-X1. I can then control the volume through the DAV-X1, but I have to completely turn down the volume on the TV itself.
Unless I'm missing something and there is a way to turn off the internal TV speakers, but still use the TV volume control to adjust volume, I'm not sure what option I have given that I have no room for a receiver. That's why I am considering using the headphone jack on the TV. That is the only way I can think of to control the volume through the TV, but still use external speakers. I just don't know what the sound quality will be like and if it would be improved at all by using an amp.