Risk is neither good nor bad. It is a combination of danger and opportunity and you cannot have one, without the other. With this definition then, here is a good way to define good risk taking behavior. You expose yourself to danger, only if you feel that there is sufficient opportunity to compensate and that you have the capacity to claim that opportunity.
Nothing may come of this, but today's Wall Street Journal carries a story about Google, trying to take a page out of Apple's retailing success, and planning to open stores that will sell Google and Google-related products. Is there opportunity here? Sure. Apple's stores are the most productive retail stores in the world, in terms of sales/square foot. Is there danger? Absolutely. Retailing is a tough business, very far from Google's current business strengths.