Dr, Ira Jacobson is fabulous and so is David Bernstein. I know the wait to see Jacobson is quite long so if you are in a rush, I'd try one of the others mentioned.
Dr. I Jacobson
50 East 69th Street
New York, NY 10021
(212) 746-2115
Dr. David Bernstein
300 Community Dr
North Shore University Hospital
Manhasset, NY 11030
Dr. Dieterich, Mt. Sinai is one of the best hepatologists (liver specialists) in the country. He is also the doctor who answers questions in Med Help's professional forum: Whoever you pick, try and go for a hepatologist (liver specialist) and not a gastro. Just be warned that many of these big league hepatologists are very busy so the more informed and prepared you are going in, the more you will get out of your visits and the treatment. So if you don't want cookie cutter treatment don't go in like a half-baked cookie :)
http://www.mountsinai.org/Other/Diseases/Hepatitis%20C?citype=Physician&ciid=Dieterich%20Douglas%20T%201770543
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Not that there are not good gastointerologists treating hepatitis C, but I would recommend a Hepatologist as they may be more up on liver related diseases such as Hep-C as they are specialists in liver diseases.