I'm shocked no one has mentioned my two faves, both from Yoda:
"Ready are you? What know you of ready? For 800 years have I trained Jedi, my own counsel will I keep on who is to be trained! A Jedi, must have the deepest commitment, hmm? The most serious mind. This one, a long time have I watched. All his life has he looked away to the future, to the horizon, never his mind on where he was! Hmm?! What he was doin'? Hmm! Adventure! Heh! Excitement Ech! A Jedi craves not these things."
Last but not least, the penultimate line from the entire saga as Yoda's face is bathed in the blood red glow of Luke's afterburners, the ghost of Kenobi intones: "That boy is our last hope." Yoda looks up at the departing X-Wing and says:
"No. There is another."
CHILLS every time! ;D