I have a large room and 6 ft tall speakers in a sub/sat set up. The sound is awesome, but I don't like the way the towers cut up my living space.
As good as 3.6s are, they suffer from the same issue that all "full range" speakers suffer, which is the fact that bass does not load properly in the same plane that mids and tweeters do. When you separate these two functions wonderful things happen to your sound stage, and coherence.
I have on order the new 6 Seres Ushers, both the 6311 and 6371s. Bass reinforcement is supplied by a powered sub which resides slightly right of center along the back wall; contrary to hype, subs do NOT work best in corners.
Considering the recent AV Monthly 6311 review, this should be sonically close enough to what I have now, but with literally half the speaker doing it. Time will tell, but I have had various sub/sat systems here, and they always sounded quite good.