Don't just choose an idea based on it's chances of success. Choose an idea that maximizes success vs. payout over time.
Pretty much everyone works from the basic assumption that 90% of startups fail. But most people put logical blinders on at that point, and treat everything as an equally risky gamble. Obviously, not every company has the same odds. Some have better products. Some have better people. There isn't as cut-and-dried a dichotomy between "big/safe" and "small/risky" as is commonly assumed or suggested.
Don't be afraid to kick the tires a bit on any opportunity, big or small. Turns out that some small startups are safer than others, and some big companies are riskier than others.