Easiest is by taxi; $45+tolls+tip. Cheapest is by AirTrain/subway; $7.25; take AirTrain from terminal to Jamaica Station, transfer to E subway to Lexington/53rd, transfer to the downtown #6 subway to 33rd St. Walk one block west to Madison and two blocks south to hotel. You can also take the NYAS express bus ($15) to Penn Station (7th Ave/33rd St) and walk to Madison Ave.
Easiest is by taxi;