I am running the CM5's with matching center and a sunfire SDS 12 sub off a denon 3312 and it powers them perfectly. You lack the phono input but Im a flac whore anyways. If you are truly trying to build a nice system then I wouldnt skimp out of just any integrated receiver. You are going to want at least 120 wpc to push them. Acoustical management is great and saves time from you placing speakers, sitting down, getting up, moving an inch, sitting down, getting up, moving them back an inch, sitting down... well you get the point. Any of these receivers that you do get I am sure you will be happy with the end results because after all, the CM5's are an amazing bookshelf speaker. I would look at some sanus stands to get them set at a god height when in your sitting position and place them far from the back of the wall (seal the enclosures with the foam if you can't put them far from the walls)
By looking at your room I wouldn't consider toeing them in because they already look close together but YMMV. I am looking into separate amplification now to pair up with these to get some ore magic out of them.. It all depends what you are trying to get out of yours..
A DAC will only work for 2-channel listening, and will be quite noticeable, with the right cables.
An amp will drastically improve dynamics, background blackness, and low-level detail (if you get the right one).