Note that people tend to risk more in poker if they have more cushion. My guess is that risk tolerance is relative (e.g. percent of your income/wealth), rather than absolute (e.g. dollar amount) for an average person. I doubt that a LWer is that much different. Google seems to weakly confirm this, but I cannot find a definitive reference.
In the open thread, moridinamael hypothesized that LWers would be willing to take more risks in order to become rich if they had a financial safety net. This seems like an idea worth exploring further.
What would you do if you had a financial safety net (maybe a year's worth of living expenses) to fall back on if your venture failed?