Need Sub and AVR advice for B&W CM1

I am planning to buy B&W CM1 bookshelf speakers for my fronts, B&W CMC center and B&W CWM 650 in-wall speakers for the rears as part of a 5.1 system.

Need advice on a good AVR and a good subwoofer to match with the system. I will be buying a new Panasonic 58" 1080P plasma. Video is as important as audio. The sub needs to be small--may only have 14"-15" of space, max. The room is about 11' by 18', but it is not completely enclosed. There is a 6' wide entranceway into the room in the back left corner.

Was thinking of new Denon 3808ci AVR or new Onkyo TX-SR875 AVR. Any thoughts?? Have no idea what i should do for a sub... If I choose to put the sub in the audio cabinet I am building, I may be able to buy a larger sub. Will the sub work just as well inside a cabinet, as opposed to being placed directly in a corner?
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Thanks Bob. I read somewhere that SVS and Hsu made better subs for the money than B&W, which is why I wasn't thinking B&W...
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Would I be better off with an Arcam or Rotel AVR than Denon or Onkyo? How much of a premium would I have to pay to step up to these brands? Is it worth it?
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Just a word of advice on B&W subs at least from my first hand experience. I'm on my 2nd ASW600 (the first one had to be returned due to a warranty issue). Both times, I found the screws holding the driver to be loose, every one. As a result, the unit produced unwanted vibration. After tightenting them up a bit, the vibration disappeared. I communicated this to B&W at their website but never received a reply. I told my hi-fi store sales person. He was surprised somewhat.
Thanks Bob. I will check out the B&W subs, as well. The SVS salesman told me B&W had nothing to compare to SVS for the same money, however, and he seemed to be saying it in a straight forward matter-of-fact way, not a pushy salesperson sort of way. I think he was recommending the sb plus 12 sub.
Thanks Pdn Sure is insightful..
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I agree with you Bob. And would probably end up going that route, if only to make the B&W salesman happy...

Anyway, my whole plan took a turn this evening as I broke the news to the wife that I want CM1's. I thought I could sell her on bookshelf speakers. She doesn't want to really see any speakers, so I am thinking about pleasing the wife and getting the B&W MT-30 system. I may not have to go this route, but my only fallback position is to mount these satellite speakers on the wall.

If I have to go this route, how disappointed will I be in the musicality of the MT-30 system, vs. the CM1 as fronts.
I enjoy listening to music, not classical or even jazz, just good rock n'roll; watching football, and movies, although I am not really a cinema freak that needs to hear Star Wars Return of the Jedi in surround sound. Will the MT-30 be a big compromise for music, or is it negligible? I need to know before I even tell the wife that the MT-30 exists.