60 Thompson is best when the rooftop bar is open (probably closed for the season but worth checking). The lobby bar is just OK.
Gansevoort is a crazy packed mob scene and that takes away from it's cool factor IMO.
Personally I would rather go hang out with Henry the bartender at Employees Only on a Fri or Sat night. He always introduced me to lots of interesting people during an evening. Regular tips will also get you regular refills.