The five cent coin with its curled up echidna may become an endangered species. http://news.ninemsn.com.au/national/2014/07/12/15/01/move-to-do-away-with-5c-coin
Slightly off topic, but when I visited the USA there was talks of scrapping the 1c coin. At one of the Smithsonian museums there was a cool coin exhibit with old rare coins and notes, and another little exhibit which asked people to vote for whether they wanted to keep the 1c coin or not. You would vote by dropping one of the coins in a bucket. The bucket which voted to do away with the coin was barely 10% full, while the bucket that voted to keep it was over 60% full.
On the next metals bull market the 5c, 10c and 20c coins will have there spot value overtake their face value. Last high they reach about 80% so the next will surely overtake.
Perhaps they could go and take away some of the copper content in the lower denominations, like the USA did with their pennies?