QTXAdsy said:
Look at Norway, they aren't in the EU (and have no intention of joining up as my ex-norwegian girlfriend told me) and are happily getting along while being close friends with their fellow european nations and (I think) have a strong economy in this money-troubling times.
Norway's vast wealth and economic success is largely due to the way it has handled its revenue from North Sea oil - it is the reckless spending of the UK's North Sea oil revenue, initiated by Thatcher in the mid-1980s and continued ever since, that contribute to our economic problems in comparison.
Successive Norwegian governments have taken a longer-term view with regards to their oil revenue (from state-owned oil companies [e.g. Statoil], tax revenue and the sale of licenses for exploration). They set up
The Petroleum Fund of Norway (now The Government Pension Fund – Global) to prepare for declining oil-related income and save necessary funds for the future to help ride out global economic crises. In September of last year the fund had a value of $654 billion, expected to reach $717 billion in 2014 and $1.3 trillion in 2030.
The UK could have had a similar petroleum fund - after all, there continue to be regular, large oil discoveries made every year in the UK North Sea (including in the West of Shetlands in 2012). However, it should be noted that Norway owns about 60% of Statoil so also receives considerable profit revenue. But as the UK government's have been too short-sighted, we are in massive debt whilst Norway have considerable surplus. Our membership of the EU (and Norway's lack thereof) has little bearing on whether this would be the case were we have a petroleum wealth fund like theirs.
To answer the original question, I am massively in favour of the EU. We get back far more than we put in, and not just in economic terms (although projects such as the EU's investment into local community schemes across the UK are often overlooked). Cross-border travel; the ability to live and work anywhere in the EU (something I'm currently enjoying in the Netherlands); advancements for human rights (again, not just in the EU); a strong judiciary system; strong UK influence on the continent (currently being eroded by the idiots we have in charge); and strong economic, diplomatic, military and social influence on the world stage.
Others have said it, but leaving the EU, or at the least being less involved in it - for example Cameron's refusal to sign the European Fiscal Compact, paving the way for all other EU countries apart from us to enact beneficial budgetary policies and to promote greater stability and growth within the EU - would be a complete disaster. The UK is on the road to insignificance, led by a short-sighted government catering to the self-serving views of a few wealthy conservative and Conservative individuals at the expense of the rest of the country.
Britain used to have key influence in the EU and it would do well to regain that, but it is being eroded away and other states are losing patience and are happy to bypass the UK on key decisions. We rely on the EU as a major (the most important) economic market for exports and cheaper imports, for subsidising our agriculture sector through the CAP, and for subsidising about two thirds of Wales, the Scottish Highlands and Islands, South Yorkshire and Merseyside - all because theses regions are economically poor and in an attempt to reduce disparity between regions of the UK. Without this EU financing, these regions of our London-centric country would be even worse off.
There's no need to lose heritage and cultural identity because we share economic and legislative organisation. There's every need to stay economically competitive and influential. Leaving the EU - even becoming less involved - would be a long-lasting, unbelievably damaging move which would permanently screw over the UK.
I had written the above mainly focussing on the economic benefits of the EU, which generally people seem to feel are the most relevant reasons for being a part of it (or not). However, Sam raises an excellent point about the arts, sciences, political liberalism and tolerance - and not least our contribution to humanitarian plights around the world as part of the EU. Membership of the EU is not just an economic consideration (although economics alone make it more than worthwhile) - education and the vast range of social improvements are also hugely important.