Today is December 1, and that means it's time to kick off our annual best of the year coverage! Over the next few weeks, I'll be polling you on your 2010 favorites and recounting the highs and lows of another year in entertainment. Today we're starting things off with the performers who made their mark on the industry this year. From potential Oscar nominees to young pop stars in the making, these are the guys and gals that just may be on the verge of becoming household names. Peruse the nominees carefully, then vote — who is the biggest breakout star of 2010?