Model S90D
Autopilot (holy crap it is amazing)
Premium Interior (very glad I got it)
Premium Sound (holy crap it is awesome)
Sunroof (also incredible)
Black Textile Seats (was the right decision for me, very nice and comfortable)
19" Wheels
Spring Suspension (very nice base suspension on it actually)
Solid White Paint (looks great!)
Dark Ash Wood (looks a lot like Piano Black to me)
Black Alcantara Headliner (very premium feel to it)
I have to say though, my purchase experience was very poor. The car already has something wrong with it (12v battery issues) and a comparable loaner was unavailable. Although the people I have worked with have been incredibly nice and seem to be great people (would love to hang out with them) on the whole the communication is very poor. It is unfortunate how bad all of that is.
BUT
Once you are in the car.. It is just so absurdly, ludicrously, amazingly, awesome that nothing else really matters.