As Europe end up with a big chaos which started by Greece, and the situation of other small countries is not better, euro been losing grown from last December and the rally down still on plus increasing. (this is why we can say euro is the weakest currency now in the forex arena) 

As the US is still fighting with inflation, & from 2008 crisis till now we seen the bearish power trying desperately to control the up trend of eurusd, but with time look like this bearish power is getting weaker, & even the euro is so weak we are not seeing a real strong dollar which push the market down, yes 1700 pips down from last December, but most of this down is euro getting weak instead of usd getting strong. (this is why we can say that usd come in the second place as a strong currency in the forex arena) 

Now when we take a look for Aud, Nzd, Jpy, we see an interesting power in these currencies and the most amazing is jpy where in many times when even usd is pushing all currencies down jpy will be pushing the usd down, in other words when usd is in full power you will see jpy stronger then usd. (this is why we can say jpy is the strongest currency now in the forex arena)