Mark Thoma writes that he will know the economy has turned a corner when the private sector is "the primary driver of new economic activity."  And he has certian things he's watching for, among them:

First, though not necessarily foremost, that banks are being recapitalized with private sector funds, and that this is happening without the aid of government guarantees or other such programs that encourage capital infusions (which is hard to determine while the government programs are in place). Second, I will want to see private sector non-residential investment improving, another sign that private sector funds are moving back into circulation. Presently, this hasn't even started heading back upward, though there are signs the decline is slowing:

Read How Will We Know when the Economy Turns the Corner? here.  And weigh in.  What are you watching for?