Hi,
I find this a very interesting thread as I am basically happy with my 2 channel system, and just starting to think about adding a center channel and surrounds. I love my Cornwalls for music, but have been very impressed with the effects of even cheap surround systems I have seen set up in stores. It seems adding an klipsch Academy center channel and a couple decent surround speakers, and the effects shoud even be much better than the cheap setups I have seen.
At the same time, a friend at work thinks the multi-channel stuff is way over rated. He would be happy with one really good speaker and a good tube amp, but puts up with stereo since you can't buy one channel media. (I think he is exagerating, but he does enjoy decent speakers and tube amp.)
Hopefully, I will either love surround sound for movies, or after experiencing it, can sell the Academy and surroud speakers for close to what I spend on them.