So starting up now, founders should ask themselves-- what's liquidity look like in 3-5+ years? The correct answer is, "I have no clue"-- but if you start now, you'll probably have a better shot at liquidity in 3-5 years because all of the other hackers went to grad school. ;-)
There is a hidden assumption in the above: it assumes that a startup's competitors are other startups, not established firms. Established firms have easier access to credit than startups. (They can fund new lines of business out of profits from existing lines of business, for example, which is a form of "access to credit" for the sake of this discussion, which is about starting new lines of business -- i.e., exploiting new markets.) This is a real disadvantage of startups relative to established firms, and the disadvantage gets bigger because of the economic downturn, but the disadvantage of being an employee of an established firm when lots of job hunters are in the market might get even bigger.
There are ways in which startups have been able to neutralize the funding advantage held by established firms. One big way is to be more agile. "Agility" means adopting new technologies and entering new market more quickly. Changes in technology and changes in markets and potential markets continue to occur during economic downturns.
On the contrary, potential startup founders will have more reasons to think of their projects as businesses - trying to grow revenues, not traffic. And to get revenue, you have to solve real problems.
EDIT: Just to be clear: That doesn't rule out enterprise applications. People in companies have needs too!