Welcome dude,
There are a few members on these forums with vaulted rooms, so hope they jump in here. My basement game/ht room is 900 sq ft with 9ft ceilings, so 8100 cu ft. My m60's and ep500 sub do a very good jump filling the room, and some times I like to crank it up a bit, when the wifey takes the kids to the mall.
Are you planning on also using a sub?
When I was speaker auditioning about 1.5-2yrs ago, I listened to B&W, Paradigm, NHT, and a few others. I almost purchased the B&W 703's as I liked the sound, but the price scared me away. To me I think the m60's are very similar if not a little better than the 703's. Price was a lot better. Not sure how Axiom can make such good speakers at an affordable price.
In my opinion the Axiom speakers are designed to give you an accurate representation of the cd your listening to. So, if you have a CD that was recorded poorly in the studio, some flaws may come out. However, recordings that are mastered of high quality will blow you away. Some people purchase speakers that are described as being "laid back", which hide or muffle what your hearing, this is not Axiom.
Depending on where you live, you might want to check out the "audition in your area" thread in the "Hearing Things" section forum. You might find someone in your area that will let you listen to their Axioms, that is what sold me.
Also, on the "Store" page, check out the Factory Outlet, if your not in a big hurry, you can save 10%...