I don't know that I really have a favorite quote, there are quotes I like and think are cool or witty for the moment but most of the time I forget them later on! Sad, I know! But this one really stuck with me.....
"Rise and rise again until lambs become lions."
- Robin Hood/Russell Crowe
(In other words, never give up! But I thought this line was brilliant and well said in the movie Robin Hood.)