i would really like to get a marantz 6400 and a surround set of def-tech bi-polars. i'm wondering though, can a room be too small for floor speakers? i know too much in home theater seems almost impossible, but realistically? i have a smaller living room that opens (split level) into the dining room and family room.
Yes, in my opinion a room can be too small for a floor standing speaker. About 20 years ago, I moved into a small flat in San Francisco with my beloved DCM Time Windows, a floor standing speaker with dual 1" dome tweeters and dual 8" mid/woofers. In a good sized room, the Time Windows were amazing, but in that small flat, the speakers just could never develop a proper soundstage. Now, the room I had was about 10 x 13 with 10' ceilings, and it was not open to another room like your home, so my experience will not be identical to yours. Still, it is a concern.
Can you get the Def Techs with an understanding that you can return them if they don't work in your room? Worth checking out.