Montezuma- 2
Moses- 2
Pancho Villa -1
Montezuma - 2
Villa - 2
David - 1 (probably existed, but as leader of a fairly small kingdom)
Montezuma II - 2 pts. C’mon, there were two of 'em, nobody tries to slight Wilhelm II’s dynastic order 
- Montezuma I. Same reason as above.
Wellington - 1 pt. Same as above.
Pancho Villa - 1 pt. In the end didn’t really accomplish much in of himself and was never really much of a national leader.
Moses - 1 pt. I’ll toss in the likeliest fictional character on this round.
Genghis Khan
Mao Zedong
Montezuma
Robert the Bruce
Victoria
I’d like to put in a good word for Attila the Hun, one of the greatest conquerors in history, who gets a bad press in part because he was a heathen fighting Christians.
Pancho Villa – 2 points (you forgot to mention my vote for him in your summary, EH, but it didn’t affect the outcome of the round. Glad he’s getting traction now)
Duke of Wellington – 2 points (see my earlier post for reason)
Oliver Cromwell – 1 point (the monarchy wasn’t eliminated for long, and it’s still around, albeit with much-diminished powers)
What good did he do? He just slaughtered and destroyed. Unlike Genghis Khan he even failed to create an international network of civilization.
2 Deng Xiaoping - An important reformer, but acted criminally in ordering or permitting the Tiananmen Square massacre of 1989.
2 Mao Zedong - One of the greatest mass-murderers of history, when you consider the Great Leap Forward and the Cultural Revolution.
1 Pancho Villa - Not really a national leader, all in all.
Creative destruction of the Roman Empire which had become corrupt. 
Attila’s empire was larger than the Roman empire and might have achieved some permanence were it not for his premature death.
“Great” is a confusing ambiguous term (which OP asks us to define as we choose); Attila was a very remarkable warrior/leader who certainly seems “greater” than many on the list.
I doubt if we can get reliable estimates for “How many deaths did [so-and-so] cause”, but I think there are several on the list who would outscore Attila by that measure.
Robert the Bruce - 2
David - 2
Moses - 1
Attila took a bad situation and made it worse. You only have a legitimate claim at creative destruction if you’re planning on creating something after you are done destroying. There’s no evidence that Attila had any such plans. He didn’t even make any plans on holding his own tribe together much less building a new society in Europe.
It’s not like he was any great role model personally either. His uncle Rugila built up the tribe. Attila and his brother Bleda took power by killing him. Then Attila killed Bleda and his other rivals. Having killed anyone who could credibly threaten him for leadership there was nobody around to take over when he died (from a stroke while he was raping a young captive) so the tribe fell apart.
The votes:
Montezuma 10
Pancho Villa 7
Mao Zedong 5
Robert the Bruce 5
Moses 4
King David 3
Duke of Wellington 3
Attila the Hun, Deng Zaoping, Santa Anna - 2 each
Oliver Cromwell, Genghis Khan, Haile Selassie, Menes, Tamerlane, Victoria - 1 each
The top four are now gone. That leaves:
Alexander the Great - Macedonian conqueror, emperor
Alfred the Great - Scholar, warrior, statesman
Cory Aquino - Restored Philippines democracy
Asoka - Early India leader
Mustafa Kemal Ataturk - Modernized, ruled Turkey
Attila the Hun - Humble, fearsome conqueror
Caesar Augustus - Founded Roman Empire
David Ben-Gurion - First Israeli PM
Otto von Bismarck - United German kingdoms
Simon Bolivar - Latin America liberator
Gaius Julius Caesar - Roman dictator, general
Charlemagne - Holy Roman Emperor
Winston Churchill - British wartime inspiration
Oliver Cromwell - English republican leader
Cyrus the Great - Great, benevolent conqueror
Charles de Gaulle - Led modern France
David - Conquered the Philistines
Deng Xiaoping - Remade modern China
Elizabeth I of England - Shrewd, determined queen
Frederick II - Ruled 1700s Prussia
Gandhi - Independence through peace
Genghis Khan - Mongol Empire founder
Mikhail Gorbachev - Reformed Soviet Union
Hammurabi - First written laws
Henry V of England - Legendary warrior-king
Isabella I of Castille - Unified, developed Spain
Thomas Jefferson - Declaration of Independence
Justinian I - Unleashed Gen. Belisarius
Abraham Lincoln - Won Civil War
Louis XIV - France’s “Sun King”
Nelson Mandela - Overcame imprisonment, triumphed
Tomas Masaryk - Czechoslovakia’s founding president
Meiji Emperor - Created modern Japan
Menes - Egypt-uniting pharaoh
Moses - Founded monotheistic religions
Muhammad - United all Arabia
Napoleon I - French expansionist emperor
Nebuchadnezzar II - Babylon’s greatest ruler
Jawaharlal Nehru - Indian prime minister
Rameses II - Egypt’s greatest pharaoh
Franklin Delano Roosevelt - 32nd American president
Peter the Great - Modernized, expanded Russia
Pitt the Elder - Noted British PM
Anwar El Sadat - Egyptian warrior, peacemaker
Saladin - Muslim leader, warrior
Antonio López de Santa Anna - Mexican nationalist leader
Haile Selassie - Ethiopia’s longtime emperor
Shaka Zulu - United Zulu tribes
Qin Shi Huang - Unified China emperor
Solon - Founded Athenian democracy
Tamerlane the Great - Clever, liberal conqueror
Umar - Expanded Islamic empire
Victoria - Noted British sovereign
Lech Walesa - Polish leader, inspiration
George Washington - First U.S. president
Duke of Wellington - Statesman, general, gentleman
The current round of voting will end on Weds. May 26 at noon EST. Same rules as before.
David - 2
Moses - 2
Attila the Hun - 1
Moses - 2
David - 2
Umar - 1
Duke of Wellington --2
Oliver Cromwell – 2
Making his debut on my list:
Attila the Hun – 1
Attila the Hun, leader of rapacious hordes who built little that lasted - 2
Genghis Khan, ditto - 2
Haile Selassie, self-indulgent, ineffective and feckless royal - 1
2 - Selassie - not in the same class as the rest
2 - David - ditto
1 - Attila - built nothing, just destroyed.
Moses - 1
Victoria - 1
Haile Selassie - 1
Henry V of England - 2
Since you guys are picking on the Scourge of God, I’ve decided to go after The Great Warrior King. His empire was much shorter-lived than that of Attila. His victory at Agincourt owes much to Henry’s rashness, French incompetence, and simple luck.
Henry’s slaughtering of his noble prisoners at Agincourt may have been justified, but his campaign 2 years later was even more ruthless:
Winston Churchill wrote:
Don’t misunderstand me. I’m not particularly opposed to Henry V, who was a man of his time and was indeed a “Great Warrior-King.” But it does seem hypocritical to praise this Christian, while condemning the heathen who was a better warrior, more loved by his people, and much more influential.
Charles de Gaulle- Deux Point 
(2 Points). Lost Algeria and was the subject of numerous assassination attempts, including one with similarities to The Day Of The Jackal.
Solon- 1 Point. It’s not democracy when most people don’t get a vote anyway.
Tomas Masaryk- 2 Points. Just not in the same league as most of the others on the list.
Attila 2
Henry V 2
David 1
Martini, Algeria was pretty much lost already by the time de Gaulle became president. I’d credit him for recognizing reality and ending an enormously expensive and unwinnable war.
septimus, not that it makes it right, but Julius Caesar also once refused to help the expelled people of the city he was besieging: Battle of Alesia - Wikipedia