Speaker Upgrade

I am looking to upgrade my speakers in the used market. I am considering The B&W 803D, Sonus Faber Cremona M, Dynaudio Confidence C-2, and Usher BE - 10.
The room is 20x20 with 18' ceilings. They will be mains in a 5.1 set up for SACD's, audio Dvd's and home theater. They will also be used when 2 channel listening. The amp is The Emotive XPA5 at 200x5.
Your input will be greatly appreciated!
Am I the only person who thinks a near CUBIC room of 20x20x18 may have some acoustic problems?
^^^ All rooms have problems unless they are treated with bass traps, first reflection zone trapping and or diffusers. A treated cube can sound great...
>>11-30-11: Taters
Take up the dealers time. It's pay back for the 80's when the dealers would not give you the time of day unless you drove a Mercedes.<<

Well let's apply this logic to a modern day scenario.

Your kids should be treated lousy in school by the same teachers who knew you were a toasted-out knot-headed stoner 25 years ago.

Yeah, that works.

I recently purchased a pair of C-1's and I think they are really great speakers. Do you use a sub with them?

I guess my comments were a bit harsh but I'll never forget all the times I was Ignored at the audio store. Now the dealers call me begging to come in and audition the latest and greatest. I mostly just buy on Audiogon and take my chances. Luckily things have worked out so far.