Escaron, welcome.
The Epic 80-500 5.1 would be a wonderful and basically future-proof choice. In a small room with a good sub (like the EP500), the M22's would also be amazing. However, in a larger room, you will not be able to attain the same SPL as you would with a larger speaker like the M80.
I would not consider a horizontal M22; it is not designed for that placement/orientation. The VP150 is Axiom's flagship center channel speaker. It will match fine with either the M22 or M80.
People seem to really like the EP350v3. But if you are looking to "buy once" since you are moving to a larger space, I would recommend stepping up to the EP500.
If you are looking to spread the purchases out over time, you could consider the Epic M22-500 5.1 now, then move the M22's to the rear and add the M80's when you move to the larger space.
I have an Onkyo TX-SR805 and think it is a fine piece of equipment. That being said, I am using M60's and the M80's are a somewhat more demanding load. There seems to be universal love for the Denon 3808CI; if you can afford it, I doubt you would either have any regrets or feel like you need an external amp.
I do not know how people feel about the 3808 remote control. My best AV purchase ever - by far - was a URC MX-700 remote. It is now discontinued, but has been replaced by the MX-850. You can get one for about $200 by calling
http://www.surfremotecontrol.com/. Some people like the Harmony series, some people don't have other family members that need to operate the system. I don't know that my family could survive without the MX-700. Just a thought for your budgeting.
