Hey Mike
Well, I've had both the N3 Tl's as well as the OB7's which I have now. They are both great speakers and I'm sure you and your wife will be very impressed with either. Now that yo have the N1X's, yo know what that Neo 3 tweeter can do, add the platinum bypass caps and take it to another level.
I'm sure you are aware that the OB's are going to need to be at least 3' offf the wall, just something you may want to make clear with the wife....
The N3 TL's are going to play down a lot further than the OZB7's, you cold easily get away withouot a sub by going with the TL's. The OB7's 4 bass drivers ( I went with the M130X upgrade) are great... really fast and tight but being they are in a sealed cabinet, they don't reach down nearly as far. You'll definitely want to be running a sub with these. If you don't want to run a sub, you could always consider the OB5 which use a ported lower cabinet
The OB aspect is wonderful. It just adds so much more dimension to the music and in a large room such as yours, I'd imgine that effect is going to be even better.... mzbrahce is right, OB is very seductive
-jay