Coffee, tea and cocoa are basically the only two sources of antioxidants in the modern Western diet. Coffee, especially, because it has up to four or five times more than tea, so it's a lot easier to get those antioxidants from it than from other sources.

Of course, like everything diet-related, you have to drink good quality coffee that's properly prepared, not the burnt crap they dish at Starbucks. And you have to dose it correctly if you develop a caffeine addition issue.