Its amazing how a really good, well setup center channel can lock in the rest of the soundfield, even outside of the dialog aspect. IMO, its best to have the center channel, unless you speaker are exceptionally good with imaging, and few are that good. The center channel can really lock in the center and entire soundfield. Its worth the trouble.
Dolby digital
I'm currently running a "Ghost" center channel. However, in Dolby Digital, I lose all of the dialogue. Do I really need to get a center channel speaker and amp to hear this, or is there a way to disable the center channel so that that audio information is shifted out to the left and right front speakers? If so, how do I disable the center channel on a Marantz AV 550 preamp/processor?