Arnold Kling from Econlog has an excellent post on the debates between economists. One of the best quote for me was:
There are economists making the case against the stimulus in ways that I find unpersuasive (Eugene Fama, for example). But the economists making the case for the stimulus are not doing a very good job, either.
There is no definitive answer. Those that are selling stimulus as the ONLY possibility are merely using a different set of value judgments than those selling the market as perfectly self-correcting. Ultimately, as Arnold says:
My advice to Will Wilkinson would be to distrust one-handed economists when it comes to macro
Economic models are incredibly useful for framing a situation like the one we are in now. However, don’t let the ideology of certain economists be more persuasive just because it is from economists.
I would add that by far the most balanced economic discussion on the crisis has come from Econlog and Marginal Revolution. And the reason that there description has seemed so balance is because they are TRANSPARENT with their value judgments – massively different to many of the other US economists on the blogsphere.