Worth noting, I think, that the New York-Singapore SQ flights is currently the longest nonstop commercial flight in the world, slightly longer than their LAX-Singapore flight. In the past, on this route, I have opted to pay up a bit more for their executive economy class. It costs more than economy, but far less than business class. The main advantage is that you get much more room ... better seat and much more legroom. Also, the seats are configured more like 2-3-2 rather than 3-5-3 or similar in economy. I highly recommend this for six-footers on an 18-hour flight.
Also, Malaysia Airlines still has, I believe, a promotion with American Express that provides two Business Class tickets for the full fare price of one when the cost is charged to an Amex Platinum card. Malaysia has upgraded its Business Class to virtually lie-flat seats in a pod-type arrangement. It's very nice, and worth considering at half the regular price (with the promo).