When I stayed at Loews Regency, I didn't have to leave Lily Beth, my min-pin/Manchester terrier mix, at home. The Regency participates in the Loews Loves Pets program and there were two bowls, a place mat, a name tag, and a big dog bed waiting for her in our room. While Lily Beth is used to sleeping with the humans in their bed, we found her passed out on the dog bed when we returned from dinner at the Regency Bar & Grill. If she was that taken with it, it must be remarkably comfortable for canines.
The Regency charges $50 per stay—at the high end among pet-friendly hotels if you are staying for only a night, but reasonable if you'll be at the hotel for longer. If your dog is comfortable walking off-leash, head to Central Park (two blocks away) before 9 am, when dogs are free to explore all 843 acres off-leash. It will surely be the highlight of your canine friend's trip to the Big Apple.