It seems a strange question. With Google having grown out to become the heart of the web, the starting point for all online activity, who wouldn't want to rank high on Google first, right?
Sure — but why? If you're a high school teen who has just setup her first web site it might be very, very important to see a page counter click up: 1 visitor, 2 visitors, 3 visitors (hi mom!), 4….
But if you're in it to earn a living visitors (traffic) is not your primary goal. Your primary goal is sales. And to make sales you need prospects.
Who are your prospects, your potential customers, and where are they? Are you sure they're on Google? And are you sure that when they are on Google, this is there entry point to not only online shopping but online spending?
Yahoo surfers spend more, for example. They also spend a lot of time on Yahoo. A large part of that time is spent on Yahoo Mail. Women use email more than men (PDF): they send and receive more messages. Could it be then that slightly more women than men user or prefer Yahoo (as was found in 2005)? Given that women online are statistically significantly better represented in not only the $30K-$50K but also the above $75K scale, isn't it interesting than to figure out how to reach them?
If so and you were to type in your best converting query in Yahoo Search — what happens? Are you nowhere to be seen? Is that good?