Despite a gain of more than 10% in the S&P 500 over the past three months, there's still a real buying opportunity in growth stocks: Our 10 best for 2011 are expected to bolster their profits an average of 61% next year -- vs. 14% for the S&P -- and yet they trade at an average 12 times next year's earnings, vs. 13 times for the S&P.