Not in an exact order, and perhaps not my absolute top 5... but these are 5 of the best! I supplied a quote for each as well. I have seen over 150 series of anime, so finding 5 of my favorite characters is infinitely too much work. This should do nicely though. :P
Kamina - Tengen Toppa Gurren Lagann: "Simon, don't believe in yourself! Believe in me who believes in you!"
Lelouche Lamperouge - Code Geass: "Inequality is not an evil. Equality itself is evil."
Senjougahara - Bakemonogatari: "If I kill you, that means I'll be the one closest to you when you're on your deathbed. Isn't it romantic?"
Konata - Lucky Star: "Drills are a Man's Romance!"
Tamaki - Ouran High School Host Club: "Just suppose... I'm not really Haruhi's father"