One thing noticeably different about the rally to 17/18k was that it seemed to be at the expense of alt coins.  It looked like everyone was selling alt coins to buy BTC.  As we've seen in the last 24 hours, that trade is very easily undone (i.e., bitcoin is sold to buy the beaten down alt coins).  The bitcoin cash rally when segwit2x was cancelled was the same kind of event.  First, it looked like everyone was dumping BTC to buy BCH.  After hitting extreme levels, that trade completely reversed over the following couple of days.  So I don't think this current rally will be sustainable unless we see new money coming into the markets.    Before we reach for $25k, I think we need a good correction that convinces everyone that the $10k-12k area is solid support.  So, unless bitcoin goes bananas when bitcoin futures start trading and skyrockets again (which could happen), I don't think $25k is in the cards this year--maybe within the first few months of 2018.