The New Year ushered in a new crop of stock market leaders. Here's a look at six nonleveraged ETFs that outperformed the stock market the most in January. What they all seem to have in common is that they lagged the market in 2011, followed by mixed returns last year. So they could be catch-up or reversion-to-the-mean plays, in which stocks that snoozed as the market leapt eventually join the leaders. Sector and country rotation occurs as