Australia:
Amex Platinum (transfers to SQ, DJ, PC, SPG and others)
NAB Velocity Visa for those who don't take Amex
USA:
Chase Priority Club Visa-$49 fee gets 1 hotel night
Barclays US Mastercard-just got it but will keep for 10k miles annual bonus
Chase CO Mastercard-just got it, will use credit limit to get Preferred Sapphire later
I mostly use Aussie cards since I live here but use US cards for US merchants that don't take non-US cards.