Re your post which included; "... Most of the stimulus was actually spent well after the GFC had passed. ..."
Many people think the GFC has not passed! Some are still predicting more doom & gloom to come.
IMO the impact is still being felt even in Australia - as per the global doom & gloom that has just seen our banks donwgraded & the XAO biting the dust yet again!
Although I missed out on Rudd's $900 I know many people who desperately needed it at that time. Given that they had paid taxes that made such a payment possible it seemed only fair that some of their money was returned by Govt. at that time.