I'm a sort of ex-pat living in Finland and I love the Euro. I can travel widely throughout Europe without being raped for around 9% every time I exchange currency.
I also work for an international company (turnover around 6 billion €), and sometimes we just choose to forget about the UK, it's just too much of a pain in the bottom to deal with. There is not much incentive to invest in our UK operation when we know that we carry the risk of currency fluctuations. We are doing very nicely elsewhere, with lest risk.
I also used to believe in Queen, country, the fact that our ancestors fought hard to prevent "Europe" telling us what to do. Nowadays, with more international exposure and experience, I have learned that much of Europe has watched the progress (more accurately, the lack of), in the UK, and have pretty much decided to let them be. If they don't want full membership of the club, then let them stew if things get tough.
The UK is now deep in the brown stuff, and will sink deeper. As someone pointed out earlier, the UK doesn't manufacture much anymore, so even when the pound is cheap, you guys have nothing to sell. All you do is receive a freshly-ripped bumhole when you want to buy imported stuff.
Analysts reckon the UK would be much better off had it joined the common currency, I for one am sad that the "British is Best" arrogance of the last 15 years has now left the economy in a worrying situation, and despite what the popularists might want to tell you, this has not been caused by Gordon the Gopher, this is something much deeper.