Thanks for all the replies!
I think the problem is that I am essentially only looking at round world redemptions (I've been convinced they're the best use of points! If you have other favourites let me know
), which in Australia pretty much limits you to Qantas and Velocity->KrisFlyer miles? And in that case I feel am much better off getting Qantas points vs any bank reward program as 100,000 bank points become 50,000 Velocity points becomes 37,000 KrisFlyer points. These are huge losses which I don't think are made up by the difference in fuel surcharges between the two.
@JohnK and oz_mark when the earn rate is 1 Qantas point or 1 bank point, the earn rate is the same, but your effective use out of the points is much higher for Qantas since you don't lose any to conversion making their "earn" rate higher than the flexible program.
Point taken about AMEX points, unless you want exactly Qantas they seem like a good option. It will just take a very long time to accrue enough points since can only get one sign up bonus/18 months? If want to build up a balance using, e.g. ANZ and AMEX sign up bonus it will cost you 2/3rds of your ANZ points to get Asia Miles or Kris Flyer miles when you could just have that amount of Qantas points instead.