I had my VP150 on a carpeted floor for a while, tilted upward toward the listening area. It sounded great that way. It's now mounted above my HDTV with full metal bracket, and it sounds no better. Re using a bookshelf speaker like an M3ti for the center, I think that would work fine also. Re M60s, if your listening is truly heavily biased toward HT, the M22/sub config is probably fine.
That said I also agree with the previous poster about M60 and stereo listening. If it turns out you listen to more more music and less HT than you envisioned, M60s would get the nod there. In any event if you have the space M60s are better. Just don't crowd yourself -- block out the floor space carefully and maybe make a cardboard mockup of the M60 to best envision the size. In theory they don't take much more floor space than M22s on stands, but in actuality they feel bigger.
Either configuration will give you really great sound. You'll be limited more by source material quality than speaker/amp issues at that point.
