There was an article in BRW last week, or the week before, comparing different CC reward systems.
There is one card (an AMP one I think), that if you spend $25k pa you can get nearly $800 worth of rewards from it, after all the expenses etc etc. Not a bad little reture, if you can always pay it off before the interest start accruing
We also use a reward system with our business c/c and cashed it in last month for $700 cash.