Given that hedge funds and trading firms employ scores of highly intelligent analysts, programmers, and managers to game the market, what shot does the average person have at successful investing in the stock market?

What's the best strategy for the average person who doesn't have time every day to follow in detail what's going on with specific companies, the market, etc? Would ETFs in growing industries be the way to go? Or is the best strategy to just stay out and go for more stable investments like bonds?

Any advice would be appreciated.