I'm still debating the single M80 vs. dual VP180 center channel arrangement. Right now I have a single M22, and it hasn't really disappointed me at all, but I still like the idea of a) having matching M80s across the front, just because it's supposed to be ideal to have them all match exactly, or b) having horizontal centers both above and below the screen to anchor the sound to the screen. I could have an M80 directly behind the screen if I went with an acoustically-transparent screen, but I don't think I want the extra expense and the slightly compromised sound and picture. I have some time to make up my mind. I'll be interested in what you decide works best for you, too.
I'm trying to prepare my wife for the long term plan (so she can at least know that somewhere down the line at least the speaker lust list has an end) so I am wish-listing the dream setup (I find that it gives me something to work toward as well). I love the two center channel speaker idea and was actually thinking about starting with the VP 180 horizontally under the screen, angled slightly up to the ear at seated positions and eventually adding an M80, placed it vertically above the screen, angled slightly down toward the ear at the seated position. I would amp them for proper power and I thought that would solve any off-axis listening issues. (Plus, they are both about the same price).
In researching that option, I've found that some audio experts warn against dual center channels (the particular responses begin 18 responses down):
http://ask.audyssey.com/entries/208239-dipoles-bipoles-or-monopoles-for-surround-speakersThoughts?
