No. If they do, the long-term pain will far exceed the short-term pain of returning to the drachma. Greece has already suffered so much long-term pain for little gain that it's hard to see them wanting more of the same.
Well, according to that Belgian dude Torie linked to, it sounds like the long-term pain of Greece not reforming its clientelistic/socialist economy will be far worse than taking the E.U.'s medicine.
Reform and austerity are not synonymous. Granted, some people will be hurt by either, but where Greece most needs reform is on the tax side of the public fisc. Not only would doing so raise funds, it would raise some badly needed political capital. However, it looks like the people aren't going to be listened to, so Greece will be staying in the Euro for the moment despite the referendum.