With just one more day until Glee returns, and eight days until the Britney Spears episode, we found ourselves thinking about the show's many guest stars. Over the course of its first season, Glee recruited guests from the Broadway stage (Jonathan Groff), TV (Molly Shannon), music (Eve), and performers who straddle all these worlds (Kristin Chenoweth, Neil Patrick Harris). And just like in the competitive world of a cappella, some dazzled and some fizzled. We've picked nine of the most prominent part-timers and ranked them from the most major performance to the most minor. And now we sit back and wait for two things: for you to weigh in with your rankings and whom we left out, and to see where Britney will fall on this list.