The Pound Sterling is down around 12%-ish against the USD, lowest since the 1980s. The Nikkei is down close to 8%, with trading suspended by circuit breakers. London banking is going to be kneecapped. Do not get that wrong: kneecapped. People wanting access to the EU in English now need to go to Ireland.
The SNP have already said that this abrogates the promises made in the independence referendum in 2014, and Scotland in this election voted overwhelmingly (and in all ridings) to stay in Europe; commentators are assuming there will be another independence vote in the next couple of years, and that it's likely it will pass. Even one of the BBC's Scottish employees said that last time they didn't take independence seriously and of course voted against, but this time, they will.
In the short term this is going to throw a chunk of money at the US and Japan, as perceived safe havens, but that'll mostly be currency; the general freak-out will hammer the markets and won't help any part of any economies. (I just saw a flash update that Dow futures are down 650 points, which is a pretty big gut-punch.)
Everyone is assuming that PM Cameron is going to stay on for a bit; possibly even a few months, until the summer Conservative Party conference, at which point there'll be a transition and possibly a new election.
This is a remarkable monkeywrenching. Even the Leave side going into tonight were talking up the idea of this being proof that people have to take Euro-scepticism seriously - not that they were going to win. And now they have a victory.
The EU needs to be scrambling now, as hard as it can, to try to figure out how to salvage the rest of the project. Europe has a long and very, very bloody history. It does not need to be starting that up again, and a lot of the hopes have been hooked to the EU.