"Best options" probably depend on a lot of things, like class of service, travel times, FF program affiliation and amount you are willing to spend.

I would hazard to say that the "best option" is the SQ (Singapore Airlines) flight from EWR, so EWR-SIN-BKK. That is their all C class A345 service to SIN and then connecting to a regional flight.

Other good options would be something like QR (Qatar Airways) flights JFK-DOH-BKK. Excellent C class product. The Y class gets pretty good grades too I believe.

Or you can take ANA via NRT. From JFK they fly their newly outfitted 777s.

Another option would be Korean from either JFK or IAD I believe via ICN if you belong to their alliance.

Plenty of choices and the option to go either TPAC or TATL. I am on an F class award ticket soon IAD-MUC-BKK on LH and TG with a return BKK-ZRH-IAD on TG and UA.