I don't really understand people who think that Britain is possibly going to get any better after leaving (economically or socially).
Firstly, who will we trade with? The US has made it clear that they aren't interested in a trade agreement any time soon, and we don't have the negotiators to arrange trade agreements or the economic strength to arrange anything with other countries particularly quickly. If we want to trade with the EU, all of the goods will have to meet European standards. So where's the advantage in leaving?
The only way to gain an economic advantage (compared to pre-Brexit Britain) is to somehow make a trade agreement with countries outside the EU (who the EU doesn't already have trade agreements set up with) and then find a way to stay in the single market as well.
Secondly, immigration is going to become a nightmare. We'll have to find a way to enforce border controls (especially hard given that the Republic of Ireland has quite understandably refused to do it for us, meaning that there'll be a route into the country via Northern Ireland anyway) that allows access to the huge numbers of people that our economy and health services need.
If Britain is going to have anybody to trade with, that'll mean finding a way to stay in the single market and that is unlikely to happen without accepting free movement of people (which is altogether great for the economy and society, but is basically the same as being in Europe but without as many of the advantages)
I think that people need to remember that Britain is not economically special. There is no magical safety net for the pound, and other countries don't really seem to care about trading with us as we do about trading with them. If Britain leaves Europe (politically, that is. Fortunately it'll still be largely socially European) then people might see just how little respect the country's really got.
I am a little bit worried about some of the stuff that people have posted in this thread, mainly regarding the British Empire. Britain came into other countries, all around the world, and stamped all over their cultures, introduced widespread drug addition in China and then crushed religious and political dissent with political imprisonments and murders, and then started enslaving people. In terms of benefits for those being conquered, I would put the British Empire far below the Romans and Persians and above the Third Reich, around the same level as Stalin's USSR. Seriously, learn your history, people.
I'm sure that there will be people out there who imagine that Britain is somehow the best country in the world, that our Empire's mass killings and enslavements were all worthwhile and that immigrants are a problem for this country. I believe that these people are owed apologies by their politicians (and probably their education system as well).
tl;dr - Britain just another country, Empire bad, economy screwed.