This is a machine I seriously considered about a year ago: . You can learn more at the bodysolid website (they used to have a larger picture and more information their but it changed a bit, now they have a video though). Notice it has real large gym type bearings on the lifting arm, adjustable cable pulley arms (a huge plus), an incline-decline bench (you never see a decline bench on these things, another huge plus!), 2:1 ratio cable system so you actually get 400lbs of resistance (giant plus!), optional leg press station, a lifetime warranty on everything (ginormous plus!) and free shipping (colossal plus! It would probably cost over $300 to ship)! The only reason I didn't buy it was that I thought it might be a bit to large for my living room
.
A cage and freeweights would be great (and cheaper), but like you said you will probably never get the wife to use it
. The K1 is easily and quickly adjustable so it's easy to for two people to take turns on it. They have some cheaper models but they don't offer the resistance or quality of this one.
I personally went with the Bowflex Ultimate at $1700 (you can get one online now for $1300 w/ free shipping) because it offered lots of resistance and folds up so it doesn't take up much space. I love it! But like I said, the K1 would have been my choice if I just had a little more space for it.
What you want in a home gym like this is quality, durability, a large variety of exercises and plenty of smooth resistance. So far I haven't seen anything in this price range match the K1. Just look at it as a lifetime investment. The only machine I've seen under $1000 that offers quality, variety and up to 410lbs of smooth resistance is the Bowflex Blaze: