Hi, I've just enrolled in several frequent flyer programs: QF, SQ, UA, SA
and CO, and I've already got nearly 90,000 miles with CX's asiamiles. I
will be flying on Emirates, Virgin Atlantic, Qantas (N class) and Air New
Zeland on HKG-LHR from this month, which means it's impossible for me
to earn asiamiles anymore. So from the above FFPs, which one would
you suggest me to stick to in order to earn as much miles as possible?
Here are the details of my flights from this month:

Apr19-Jul1: Emirates HKG-DXB-LHR (Booking Class: K)
Sept1-Oct13: Virgin Atlantic HKG-LHR (Booking Class: X)
Oct28-Dec18: Qantas (Booking Class: N)
Jan8-9Feb: Air New Zeland (Booking Class: Currently O/E, may change
to the lowest economy when fares are opened)
18Feb-30Mar: Air New Zeland/Virgin Atlantic (Booking Class: X)

Thanks for reading and helping!

As QF isn't a partner of SA Voyager anymore, you won't be able to credit all miles to one program. Obviously SA or CO seem to be the top choice, but with the cheap booking classes you have to go deep into the smallprint.

SA: VS, EK, NZ
CO: EK, VS, QF
UA: EK, NZ
SQ: VS, NZ
US: QF, NZ
SK: QF, NZ
BD: VS, NZ
DL: EK, VS
NH: VS, NZ

SA just released a new program guide but I don't know about the (dis)advantages of SA's program, maybe you get more on this in the "Other ME/African FFP" forum.

Thanks, by the way CO miles accural is only valid on Trans-Pacific QF
flight so this left me SA only.