I don't lean especially either in favour of UK membership of the EU or against it, given the current political climate. In an ideal world we would withdraw from the EU, declare open borders or something not far off, and put the savings from leaving the EU into reducing the deficit. Realistically, withdrawal from the EU would lead to lower immigration into the UK, and any savings would just wasted in the same way that most government spending gets wasted.
What is (in my view) a serious issue, though, is uncertainty regarding British membership of the EU. So long as there is uncertainty over EU funding, immigration, tariffs, and all the other things which governments stick their greasy paws into, businesses will be reluctant to invest in projects which are reliant upon these uncertainties.
For that reason, my opinion regarding an EU referendum is "If it were done when 'tis done, then 'twere well It were done quickly." Pushing a referendum back to 2018 might change the result, but it also creates two or three years of uncertainty which the markets will hate. If there is going to be an election, it should be held either in October 2015 or in May 2016.
It should be made clear that I see this as the best course for the UK as a whole. My personal interests would be very well served by a referendum being pushed back to at least 2017, given that I intend to spend the next two years living in Budapest. So long as the UK is in the EU, I can just turn up there, fill in a few forms, and live there indefinitely without the Hungarian state demanding all that much money to leave me alone. If the UK leaves the EU, then I'll need to sort out a visa (expensive and fairly time-consuming).