Speaker placement ALWAYS makes a difference. What kind of difference depends on your room. Overall, I believe that the full-form-factor M22's are the optimal choice (rather than the inwall/onwall/cabinet/etc versions).
Axiom stands seem a little pricey to me, but I'm sure they are excellent quality.
You should get fine performance from the M22's no matter where you place them, but boundaries, enclosures, obstructions and the like can make a very meaningful difference. Nothing is as good as having them basically "in free space" (on a stand with nothing nearby) but I live in the real world and suspect you do, too.
Just do whatever looks and feels "right" in your room, with the goal of trying to get them away from as much other stuff (including wall boundaries) as possible.
Edit: forgot about the center - generally, vertically-oriented speakers have more uniform off-axis dispersion than horizontally-oriented ones. Lots of folks here swear by a vertical center, but it certainly has to "work" for your room.
Last edited by tomtuttle; 01/12/12 03:10 AM. Reason: D'oh
