After reading horror stories about getting taxis at HCMC airport on this and other forums I was pleasantly surprised when I arrived on Friday 13th March 2009.
Just past the customs check are about 4 or 5 money changes, all offering the same rate and all selling taxi to downtown for US$8. The company was SGA, the cars were large and quite new and you are walked to your car by a charming young lady.
The trip to District 1 took about 30 minutes at about 6 pm. No requests for extra fees or payments. An excellent service.
Even the money changes at the airport were a pleasant surprise. I got 10,741 VND for my A$. The following morning around District 1 the rate ranged from 10,400 to 10,900 VND. They also sell MobiFhone sim cards.
Nothing but positive comments from this (my second) arrival through HCMC airport.