Cipolla Rossa is, indeed, terrific and BYOB. Another good UES BYOB is Square Meal on 92nd just west of Madison in the old Joanna's space. It's owned by Yura and is essentially a very well prepared comfort food menu.
Just went to Square meal last night and could not recommend it more highly. The food is solid and the atomsphere and service were wonderful. Didn't rush you, no corkage fee. Felt like a nieghborhood place and they seemed to know many of the diners
I second cipolla rossa. No corkage, food very authentic italian, have great calamari too, fantastic game--the boar meatloaf and venison ragu are faves.. Atmosphere not the greatest but the food is so good, you won't care. would make a rezzie as they are getting a following.