any restaurants open on Xmas day ??
Many restaurants won't know or publicize being open on Christmas Day until late November. While some restaurants are open, many are closed. They usually make announcements just after Thanksgiving. I'd check the local magazines, Zagat.com, and OpenTable.com then.
Chinatown can also be an option if you're willing to wade through the crowds (it's extremely popular on Christmas Day, especially with the Jewish population of NYC). Nearly every Chinese restaurant in Chinatown is open, but with 1-2 hr waits.
What are you willing to spend per person, including tax, tip, and wine/drinks?
If you have the budget, I would look into Maialino, Momofuku Ko, and Jean Georges, who were all open for Christmas Day dinner in 2009. All three of these are "special occasion" type restaurants and pretty expensive, but I did Maialino for Christmas Eve last year, and it was great!
Another favorite of CHers for Christmas Day dinner is the River Cafe, but that is in Brooklyn. Marseille and Cibo have also been mentioned positively here in the past.
Also in past years
BTW, last year Zagat reported these places were open on Christmas Day: Adour, Armani Ristorante, Benoit, BLT Market, Blaue Gans, Carmine's, Cornelia Street Cafe, David Burke Townhouse, Fishtail, Kittichai, Le Bernardin, Macao Trading Co., Rouge Tomate, SD26, Tamarind.
Additionally restaurants affiliated with hotels tend to be open.
1 Central Park W, New York, NY 10023
1430 6th Ave, New York, NY 10019
155 W. 51st St., New York, NY 10019
Cornelia Street Cafe
29 Cornelia Street, New York, NY 10014
60 Thompson St, New York, NY 10012
767 Second Avenue, New York, NY 10017
139 Duane Street, New York, NY 10013
163 1st Ave, New York, NY 10003
10 East 60th Street, New York, NY 10022
Macao Trading Co.
311 Church Street, New York, NY 10013
2 Lexington Avenue, New York, NY 10010
19 East 26th Street, New York, NY 10010