My favorite sniper was Emile. He could hit anything at all, from the most insane distances. Funny thing was, his stats weren't even that great. He was only moderately above the other soldiers, yet he was incredible. Just one of those ghosts of the machine, where the code does things it shouldn't.
His sister (same last name, I'm assuming here) was also really good too come to think of it. Genetics, maybe?