I'm not really sure what people expect from a centre channel. It's primary duty is to relay vocals, anchoring the left and right channels across a front soundstage.
It's purpose is not to provide bass or the sound range expected from the main speakers.
I've never understood why people seem to think they are "missing" something because the surround speakers and centre channel are not as large and big as the main fronts.
Newbie, don't be alarmed, Chess did not mean to go after you. I think his point is that many people here use the 150 without issue when compared to M80s and M60s. I don't agree with his global statement that a center is less critical, than the sides. I'm too lazy to pull it up, but I think something like 80% of a movie's sound is center channel. And if the M60 will recreate audio in the 80hz to 350 range better than a 150, then you gain from it. I have never heard that movie studios remove the bass or mid-bass from the center channel. If they do, and no deep mid-bass and bass goes the center, then fine. Otherwise, i can't agree as the M60 should be "better" than the 150.
The VP150 clearly does a fine job and would (and does) suffice for many great HT. But you won't be any worse off with M60. I think this setup would sound great and most people would do it if center channels were not a difficult fit in a vertical setup in most systems. I expect the M60 to sound very close to the M80 and your HT should sound great. I would expect the M60 to be better than the 150 in almost every respect, although the difference is likely only found at the edges of their performance.
Let us know how it sounds. Surround audio should rock and all sounds moving across the screen should be completely smooth.
Edit: never mind, Grunt has real information to offer. My opinion is rather useless compared to his experience -
because he generally agrees with me. 
