Why not just add a TV to your two channel system? We love watching TV and movies through our stereo, and never miss the extra channels of audio. We did invest in a very nice TV, one of those that renders black as very black; and it was well worth the money. For sound, I just grab the audio from the back of the TV with an optical cable and into the DAC-60 card of an Accuphase E-5000. And, by saving the expense of three or even more extra speakers, all of the investment can optimize the stereo pair. In our case, it's a pair of Borresen Z3 Cryos. We do have a pair of subs too, and the sheer power of this system imbues movies with most of the visceral sound one would get in a theater.
Regards, Oran