Well, we've just returned from a romantic escape to NYC, a place we have been going to since our fifth date weekend...... some advice on making NYC "romantic" --- allocate money to experiences, rather that hotel room, and spend to minimize travel hassle for more togetherness.
For a relatively quiet hotel in NYC, there are two things I look for: A middle-of-the-block location on a street (not an avenue), and the least number of rooms per floor for minimal hallway traffic and most sense of privacy.
With those criteria, we've been happy with the bare-bones Marriott Fairfield Inn-Chelsea on 28th St between 6 and 7 Av. Only 7 rooms per floor, so very little hall noise. That block on 28th St is mostly flower and plant stores, so it's quiet at night.....and everyday we pick up lots of fresh flowers for the room.....that plus a few flickering candles makes the simple hotel room romantic (imho)!
The other thing my partner appreciates to keep NYC romantic is minimizing the travel hassles....money saved on hotel room can go to limo/car service to/from airport and buying an unlimited metrocard subway/pass, which is $29 for 7days, even when we are just there for 3-4 days, so there's no second thoughts about hopping on bus/subway just for short distances when feet are tired.
For art viewing, there are a couple of "old art" museums we like to see for the architecture---the Frick mansion and the Morgan Library (free on Friday nights).....and for modern art, if you can venture out of Manhattan, Judy Chicago's iconic "Dinner Party" is at the Brooklyn Museum, and the larger exhibitions from Dia are in Beacon, NY, an easy Metro-North commuter train ride
http://www.diabeacon.org/sites/main/beacon
http://www.brooklynmuseum.org/exhibitions/dinner_party/
Enjoy---- this post caught our attention because we fondly remember the Zurich Park Hyatt as highly romantic.....for both the sexy shower/bath combination and the rich ice cream place across the street!
Oh, and I'm reminded of our experience at the uber-trendoid W Union Square soon after it opened..... from their DVD library we chose "The Sweet Smell of Success" as our midnight movie, but the W's all-knowing video librarian said it was poor choice and tried to get us to change. On the elevator ridfe back up to our room, another guest noticed the DVD box, smiled and said "what a perfect Manhattan movie for a stormy night", then recited the cast list and awards......we got off on the same floor, so I put him on the house phone in the hall to finish my needless debate with the W's video desk! So, like you, we'll avoid the we-know-better-what-you-want boo-tike hotels.