Daniel Gross says it's too early to tell:
Perhaps the biggest mistake stimulus proponents made was to suggest that this recession would (and could) end quickly. Modern America is not equipped—financially, socially, or psychologically—to deal with long recessions. We don't have the safety net or the savings to cope with a protracted downturn. And fortunately, we haven't had to. The last two recessions, which ended in 2001 and 1992, respectively, lasted only eight months each. But recessions brought on by financial crises are always deeper and more long-lasting than other recessions, as economists Ken Rogoff and Carmen Reinhardt show in this paper. By February 2009, when the stimulus package was passed, the recession was already the longest in 28 years; now it's the longest contraction since the Great Depression.