Welcome to FT! For me, the primary driver would be airline alliance and mileage accrual. (This is FT, afterall.) If you want to fly Star Alliance, the CO/SQ itinerary sounds good. If you're a OneWorld guy, flying CX via HKG works well.

If you're just trying to save money, you'll have to do a lot of comparison shopping. Leaving from JFK or LAX is probably your cheapest option to Asia, and you could fly into SIN or BKK, then connect on one of the low-fare Asian carriers like Firefly, Air Asia, Tiger, JetStar, etc. Buying all those separate tickets would be risky because you're not protected if you mis-connect, but it might be cheaper. You won't know until you run the numbers.

Looks like CI (China Airlines) is selling LAX-TPE-KUL for $1,353 right now and SQ has $1,339 SFO-ICN-SIN.

Good luck! Let us know what you decide.