Here is a post containing advice from Randy on choosing a FFP.

If you are flying lots of business or first (econ doesnt count) class on SQ dont forget that you could get status in 2 programs by way of PPS Club. (Miles go to any FFP by SQ recognises your loyalty as well. See lots of threads on this in the SQ forum.)

You may have noticed NZ Airpoints is changing from Nov 04. There is a substantial increase in earning (AIrpoints Dollars as well as status) for business and first class. However this is tempered slightly by lower rates for itineraries that include any airline other than NZ on any leg (the lower rates also apply to the sectors flown on NZ).