If you're fixed on Malaysia and HKG, you don't have a big choice. For the best discounted prices you need to stick to one airline. For those two countries, you're limited to Cathy which hubs in HKG. Now if you don't mind a 4hr bus ride (quite comfortable) out of Singapore, or doing an internet air ticket to cover SIN-KUL on AirAsia or Tiger (can be extremly cheap.... cheaper than the bus) than you can do a YVR (or SEA) to HKG and SIN. That opens options up to include United (from SEA) and SIA. A few years ago, Malaysian Airlines flew here, and transitted HKG on the way. That would have been perfect. Unfortunately they stopped YVR.
If you can forgo HKG, or take an extra transit point (longer trip) than you have China Eastern (via Shanghai), Eva/ChinaAirlines (via TPE), Asiana/KoreanAir (via SEL), JAL/NW (via NRT), AirChina (via PEK).
I have heard China E. is really discounting deep ($600 return to Shanghai right now). But travel in July is peak, so expect a minimum $1K. At least $1,600 for Cathy. Yes, you can save a few hundred if you buy your tickets out of the US for travel through SEA. However, not all the above airlines service SEA.
A decent, small Richmond-based travel agent should know all these options and have access to the wholesale discount tickets from these airlines. The bigger travel shops don't deal in these deep discount tickets. They may not be too open with pricing over the phone (for competitive reasons), so plan on visiting a few.
I travel about 150,000 miles a year across both oceans, and been on most of these airlines (and AC) when doing Asia. Safer than any drive up the 99. Good luck with your shopping.