from the manga Gantz. haven't read it myself, but this page is just great.
from Eyesheild 21 when the main character Sena tells the other character Kurita that he's not actually there to join the football team. the expression on his face is priceless.
but yeah, i guess these should technically be in the funny pictures thread, but they're parts of comics, so i'd say here would be a good place for them.