Here is a list of all the Saint Patrick's Day parades in NYS:
A Complete list of all 2008 Saint Patrick's Parade in the State of New York (NY)
I used to play in a police bagpipe band and have marched in mnay of them. If you want a more local feel for the holiday you can check these out.... most of them have some local parties or bars that are really a good time.
Bay Ridge, Brooklyn (can't go wrong here)
The Brooklyn Parade in Park Slope (relatively new but I have heard its good time)
Mount Kisco, Westchester
Pearl River (outstanding parade)
Rockaway Beach (hit or miss, buts tons of pubs to visit)
Rockville Centre, LI (one of my favorites)
Staten Island (used to be better has been a little rowdy in the recent past)
Throgs Neck (another good one)