From my experience:
MoppyO- Was the top attacker in grepolis for a long time, absolute machine. Although could be a handful sometimes when she put her mind to it she annihilated anything in front of her
Whiskdelta- Another great player IMO, brilliant at sniping and aggressive.
Hilop- Best sniper I have seen in the game
Socrates-Normally no.1 player, excellent attacker, defender and leader
Milos21- Same as socrates
Ford Prefect- Sadly left the game a while ago I think, but a good friend, aggressive player and a great guy to have in any team.
Perhaps you could add best leaders to this?