Reasons it is hard to get bullish

Stimulus or no, it is going to be difficult to see a sustained improvement in the economy or the market without a functioning banking system.  The Fed's liquidity programs, the zero interest rate target, and the quantitative and qualitative easing all go in the right direction, but if the financial system remains too big for its economic britches, the credit transmission mechanism will remain in slipped clutch mode because every bank will be quite rationally worried that downsizing means them.

This makes the problems with commercial real estate, and banks heavy exposure to these problems, yet another shoe to drop in this crisis.  CR has the quote and the context.

The delinquency rate will likely hit 3% by the end of 2009, its highest point in more than a decade, says Richard Parkus Deutsche Bank's head of research on such bonds, known as commercial-mortgage-backed securities, or CMBS.

 

This is not only a problem for CMBS, but many banks and thrifts have excessive exposure to CRE loans:

 

 According to research firm Foresight Analytics, soured commercial mortgages on banks' books jumped to 2.2% as of the third quarter of last year, from 1.5% at the end of 2007. The research firm estimates that the rate could rise to 2.6% in the fourth quarter of 2008.
...
Banks and thrifts would suffer in a commercial-real-estate downturn because they own nearly 50% of all commercial mortgages outstanding. ... According to Foresight Analytics, as of Sept. 30, 2008, some 1,400 commercial banks and savings institutions had more than 300% of their Tier 1 capital in commercial mortgages.

Distressed investors of the world unite!  You have nothing to lose but your shirts!