Jan Loeys, chief market strategist at JP Morgan says in an investor note on Greece and the euro:
"The risk scenario of Greek exit from the EMU is a drama for Greece, but in this analyst's view, not for world markets
Claims on Greece are concentrated at the European Central Bank and EU institutions"
He is quoted in a Bloomberg article, which includes similar from other analysits:
"The euro's collapse is unlikely because markets have already priced in such risks. The Greek problem isn't shaking up Italy and Spain."
More at that link