The X1 is a great car.
I went in with the iDrive system being optional, but now I don't think I'd be willing to go without it. Mostly for how well my iPhone integrates with it for music.
I also have and love the xenons, but can't say if they are a must have or not as I've never driven an X1 without them in the dark. Comfort access is nice to have since my wife occasionally likes to drive it and this way everything automatically sets for both of us.
Personally I would recommend going the CPO route on anything used.