I've done this type of thing before. Personally, I find surround sound annoying. If stereo is your main concern, don't compromise your 2 channel system at all. The first thing you need to do is hook up your video source up to your main system and just see how it sounds. You can probably stop there without changing a thing. If not, you may have to get some separate HT components. At that point, it becomes hard to make a recommendation because there are so many different paths you can take to get the results you are looking for. For example, you may go with a receiver and some passive speakers, or a HT preamp and some powered speakers, or some type of combination. Its possible to use your current equipment and get a HT preamp with a pass through option, or don't touch it at all and just work around it. In the end, whatever you do will have to be based on decisions that you make. For me, as long as I can hear it, its good enough for me. I don't need much more than a TV with built in speakers. Most likely, what ever you choose will be somewhere between my basic needs of TV quality audio and your current 2 channel system.
Here's a couple of things you may want to consider. If you end up going with a centre channel, you may not want to buy one. The reason for this is that I find typical centre channel speakers are almost always over powered by the main speakers. You can always buy your way out of the problem by getting more expensive/powerful/bigger etc.. centre channel gear or just get a regular pair of stereo speakers. Put 1 speaker on each side of the screen and get a stereo amp (Or 2 powered speakers). Feed the same centre channel signal to both channels. Doing it that way makes it so much easier on the equipment. Just think how much more you would have to ask of just 1 centre channel to get similar results. Another benefit is the imaging. Its just like listening to a mono recording. You get a rock solid, stable image, that's very clear. The only other thing I would suggest is not to bother with side or rear channels. Its just not necessary. The system should sound fine with out them.If you like surround, thatÂ’s another matter. No reason to buy something like that unless you really want it.
Here's a couple of things you may want to consider. If you end up going with a centre channel, you may not want to buy one. The reason for this is that I find typical centre channel speakers are almost always over powered by the main speakers. You can always buy your way out of the problem by getting more expensive/powerful/bigger etc.. centre channel gear or just get a regular pair of stereo speakers. Put 1 speaker on each side of the screen and get a stereo amp (Or 2 powered speakers). Feed the same centre channel signal to both channels. Doing it that way makes it so much easier on the equipment. Just think how much more you would have to ask of just 1 centre channel to get similar results. Another benefit is the imaging. Its just like listening to a mono recording. You get a rock solid, stable image, that's very clear. The only other thing I would suggest is not to bother with side or rear channels. Its just not necessary. The system should sound fine with out them.If you like surround, thatÂ’s another matter. No reason to buy something like that unless you really want it.