I'll keep it brief.
Leave, exchange rates fall because of the fact that we import 54% of our goods from the EU inflation goes up, interest rates go up to combat this and as consumer incomes fall a recession ensues. This combinded with the ecomic uncertainty means that UK firms hold back on investing, FDI falls too, and the recession will be quite deep and painful.
Now thats short term. Long term it depends on the trade deal struck. If we strike an EEA style deal then it will be almost business as usual, with less say and still contributing.
The ideal trade agreement would be to get complete access to the single market but not have to pay any of the costs. However, to address Bronze's point about trade, EU businesses/states will not accept having to follow regulations, contribute in tax form etc and UK firms getting to be more competitive through not having this. Yes both will lose out, but when you work out that 3million jobs here rely on EU trade and the 5m across the other 27 member states the impact will be felt in a far smaller way.
To reiterate 15 % of EU exports come to the UK, 44% of UK exports go to the EU. The importance of EU trade to the UK is far higher than that of the USA or Canada, they also don't share borders, or import as much from the EU as we do. Its not a comparable situation.
So that trade deal isn't forthcoming, we'd have to accept some form of freedom of movement and contrubuting in some way. We may get better terms than Norway or Switzerland but not massively different. Why? Because to get the deal brexiters want would be to destroy the EU and its bargaining power at any trade negotiation.
We'd also have to organise new trade deals with South Korea, China and other countries which would take time. With a smaller market to offer them we would have to accept less beneficial deals.
The effect on the UK would be massively detrimental, job losses, higher costs of living, lower tax take, poorer services.
Long term this is very detrimental to the UK economy, because we will have less to invest into education, health and infrastructure effecting the long term capacity of the economy. On top of this we will be less attractive to FDI also effecting our Long run prosperity. Firms may also decide to leave the UK, HSBC is seriously considering it.
A hope is that the lower level of the pound encourages more exports, however it depends on the Marshal Learner condition being met, and as a large number of our exports are high end goods they tend to be price inleastic!
The is a possibility that Scotland will sceede from the Union if a majority of Scots vote to remain too.
Of course this is hypothetical, but I've read the independent PWC report, and other analysis from economists and banks etc. There are none that are too hopeful.