Thanks all for the feedback! I do value my United miles more than my AA miles because it's easier to redeem on UA (in my opinion) and I have close to 200,000 miles on AA that I'm trying to use up. With that said, here are both itineraries:

Depart:
14:20
Sat., 29 Dec., 2012
Frankfurt, Germany (FRA)
Arrive:
07:00 +1 Day
Sun., 30 Dec., 2012
Beijing, People's Republic of China (PEK - Capital)
Flight Time:
9 hr 40 mn
Flight: CA966
Operated by Air China.
Aircraft: Boeing 777-300
Fare Class: Business (I)

Change Planes. Connect time in Beijing, People's Republic of China (PEK - Capital) is 1 hr 45 mn.

Depart:
08:45
Sun., 30 Dec., 2012
Beijing, People's Republic of China (PEK - Capital)
Arrive:
15:25
Sun., 30 Dec., 2012
Singapore, Singapore (SIN)
Flight Time:
6 hr 40 mn
Flight: SQ805
Operated by Singapore Airlines.
Aircraft: Boeing 777-200
Fare Class: Business (I)

Change Planes. Connect time in Singapore, Singapore (SIN) is 4 hr 20 mn.

Depart:
19:45
Sun., 30 Dec., 2012
Singapore, Singapore (SIN)
Arrive:
10:35 +1 Day
Mon., 31 Dec., 2012
Christchurch NZ (CHC)
Flight Time:
9 hr 50 mn
Flight: SQ297
Operated by Singapore Airlines.
Aircraft: Boeing 777-200
Fare Class: Business (I)

I'm concerned by the less than 2 hours layover in Beijing - according to reports I've read that may not be sufficient to transfer and I may miss my connection, which would be terrible as the SIN-CHC flight is only once a day and if I miss it, I'll have to fly on New Year's eve and that would defeat the point of me going there.

Here's the OW itinerary:

Flight CX 250
Operated by Cathay Pacific Departure: London (Heathrow)
Terminal 3
Date: Sat 29 Dec 12
Time: 18:05
Arrival: Hong Kong
Terminal 1
Date: Sun 30 Dec 12
Time: 13:45
Meal: Dinner / Breakfast
Total duration: 11h 40m
Aircraft type: Boeing 777-300ER

Flight CX 111
Operated by Cathay Pacific Departure: Hong Kong
Terminal 1
Date: Sun 30 Dec 12
Time: 19:00
Arrival: Sydney
Terminal 1
Date: Mon 31 Dec 12
Time: 07:15
Meal: Dinner / Breakfast
Total duration: 9h 15m
Aircraft type: Airbus Industrie A330-300

QF 47
Operated by Qantas
Sydney (SYD)
December 31, 2012 09:30 AM
Travel Time : 3 h 10 m
Cabin Class : Business
Wellington (WLG)
December 31, 2012 02:40 PM
Booking Code : U
Plane Type : 73H

If I've missed something, let me know!