Which is better, Dow Jones or S&P 500?

I want to invest long term but I do not have much faith in U.S markets. I want to be a little risky but with US currency already weak I don't know how much risk I really want to settle with. What do you recommend with these two indexes? Can you give me a bottom line? CNN Money is great for those who know the financial lingo. I am just starting out and need a crash course. Is that even possible?