42" and the couch sits about 9 feet away. I have rear speakers, but I haven't gotten around to installing them since I moved in (nearly two years ago). Now I am planning on moving this summer, so let's hope the next house accomodates the set up a bit better.
As it currently stands, my couch butts up against the wall, leaving me limited options for speaker placement. When the wife and kids are home, I rarely get a chance to watch movies at the appropriate level anyway, so I have a nice set of headphones that allow me the comfort of watching a movie without disturbing the rest of the house. On the occasion that I do pull out the surrounds and string up some ad-hoc cable wire, the speakers are on either side of the couch, slightly above ear level, about 4'-5' from my head.