The United Kingdom, thank God, is not a member of the Euro zone.
The Euro zone was created largely by the French/German axis to protect their own fiscal interests. The Euro zone is fine as long as "minor Euro zone members" (all Euro zone members other than France and Germany) don't go bust. Cameron is right not to want to give more powers to Europe, when it is entirely possible that the whole project is doomed to go down in flames.
I can't imagine Merkel and Sarkozy being too happy with the idea of bailing out another 2 or 3 bankrupt Euro zone members.
The EU is not working in an economic sense. Britain should look to other markets for its products. Britain has at the moment a 60% income from the EU. This is too many eggs in one basket. Diversification of trade away from the EU system would leave Britain in control of its own affairs without the interference of the EU and its uncontrollable administrative systems.
I have to say over the past 15 years I had become very cynical concerning politicians, but Cameron is slowly restoring my faith.