I think Japan is next.
Most of Japan's debt is held by Japanese citizens, unlike the Europeans. It's the foundation of their retirement and pension programs. Thus, they can delay a lot longer by working later in life, whereas once the writing goes up on the wall that your country may not be able to pay back its debt, nobody is willing to loan you money, thus interest rates go up, thus the ability to repay bondholders goes down and you have a vicious cycle. That's what happened in Greece and is unfolding in Spain, Italy and Portugal today. Since the Japanese are buying their own bonds, they can prop their own system up a lot longer. Will it come apart eventually when folks retire enmasse, you bet, but they have a lot more control over the how and the when than Spain does.
Ireland is perceived as being a culture that is very willing to suffer, thus, they're still seen as a better risk, but no doubt about it, they're in for a lot of suffering and only time will tell if they eventually see the rebellion against austerity that Greece has demonstrated.