I guess it´s kinda obvious since I´m finnish, but Simo Häyhä of course!
Some facts about Häyhä:
-505 confirmed kills (some estimates say 542)
-He used only iron sights, because with a scope he would´ve had to pop his head up higher
-Longest kill 490yds (450m), also with iron sights
-He survived an exploding bullet to his face (search him on wikipedia and you´ll find a picture of his face)
Vasili Zaitsev only had 235 kills, altough I´m not saying he was a bad shot, Häyhä was better