I too wouldn't be much surprised if we reach $500 even before the end of this month.
I'm simply considering the fact that BTC has gained about 40~45 in the past 5-6 days and for now it seems that this trend is continuing.
Now there're 5 remaining days to increase another $35 and achieve that goal... It seems not impossible to me.
I think we will attempt $680 before the halving
That would be terrific: I think it's a crucial point!
685 is the ATH from the beginning of June 2014 until today.