It's a tough one. On the one hand it's easy to get bitter about these bonuses. On the other hand the banks will lose people who (despite the mistakes they've made) are the most experienced in their fields when it comes to handling the banks and won't be able to attract staff of any quality without the bonuses as it's a systemic issue.
On the other hand as other smart people on this site have pointed out, where the government has lended or invested it should have a say in the decision.
Personally I'd be happy to let them have their bonuses providing their balls were strapped to a device that checks the stock price every 30 seconds and administers electric shocks when the share price drops below a certain level. If they manage to make it through the year without singed balls or resigning from the pain, I think they might deserve the bonus.