I like the Australian notes, they're brightly coloured yellows, oranges, greens etc. even the UK notes are fairly nice to look at, plus they're very security laden with silver foil strips and watermarking.
In the future, maybe 10 years time, I see us using bank notes a lot less in the developed world as we'll be using credit/debit cards and mobile phones to pay for goods & services.
The 'Tuxedo' card [from Mastercard] has been advertised over here recently and you can only spend what you've paid onto it. I can see this kind of card being used a lot. Not just as a way to curb debt but as a replacement to cash.
Right now I rarely use cash as it is, I use it to buy the occasional drink at a pub or a pint of milk at the shop. That's only once a fortnight. As such I'd be happy to use an alternative payment method.
It'll be cool when we can walk into a shop and not have to carry any form of payment, we can just have our retina's scanned which will hook up to our bank accounts
