As talk of Greece's debt "crisis" becomes increasingly dire, I believe the best course of action is for the United Kingdom and its Sterling to be ushered into the fold of the Euro.
The United Kingdom is strong; its economy is strong and its currency is strong. The European Union cannot exist as a collection of hand-picked members to an elite social club; it is and must be nothing other than Europe. The UK must become part of the EU, taking advantage of the fact that they could effectively "eat" the debt of Greece, Spain, Italy, Portugal AND Ireland, and be able to grow their way out of the debt through sheer strength of GDP.
Initially this would weaken Britain, but it would strengthen the entire EU and lead to prosperity. Germany cannot carry the EU alone; it needs a 2nd Germany.