Although I have a big closet compared to most in NYC, I think Aerin Lauder's closet/dressing room/office is bigger than my entire apartment!
Not only is her closet huge and ridiculously organized, look at those jeans, and I thought I was anal, but it is lined in ridiculously expensive hand painted wallpaper from Gracie. It is beautiful though and apparently very popular, Tory Burch also has it in her entry foyer.
Vivre owner Eva Jeanbart-Lorenzotti's closet that has been featured in Domino among others, is a bit more reasonable in size but no less well organized. I love the mirrored doors on her eveningwear closet. It's a great idea for less worn items.
Sally Perrin's closet in LA that was recently featured in Bazaar looks more lived in and less styled to death. I love all the personal items and photos on her dresser.