Did anyone notice Harry never used avadavadavra on anyone, even Voldemort?

Yes, he never did! His signature spell was 'Expeliarmus'! Maybe because he always wanted to defend himself and only hurt his opponent when necessary! Another thing that makes him awesome :D

Because he does not go around killing everyone in his path that is Voldemorts job.

He doesn`t use the Avadacadavra on anyone because, we know that in all saga he doesn`t want to become in someone like Voldemort (even if he actually is a Voldemort Horrocrux) so not using the Avadacadavra is his way of figth against Voldemort and demostrate that he is better than him.
I think is part of his pure nature cuz he is a good person, he can`t kill someone and then expect to live well the rest of his life...

well that is sort of a good thing because then he's not a killer

Yes. That was kind of the point of his character.

yeh well harry is not a killer, he usually wished to disarm his opponents and only hurt them if necessary :)

Wait - i never noticed this - so how did voldemort die in the end then? all of his horcruxes had been destroyed which meant that he was mortal and able to be killed but surely harry didn't finish him off with a disarming spell?

i don't think harry wants to use the spell that killed his parents. also, crucio and imperio dosent kill

because he's a good guy!!!!! ;p

Yes that's the point! :]
He was able to defeat Voldemort without using the Killing Curse at all - that's pretty cool!