These three, all military (shocker, right?), immediately came to mind...
1. Napoleon - I'd advise against the Russian Campaign, specifically the Battle of Borodino
2. Dwight Eisenhower - would love to be in the SHAEF HQ during the first two weeks of June '44
3. Scipio Africanus - Roman general that defeated Hannibal, never lost a battle and had a continent named after him
But as I was making the list I knew it would be Thomas Jefferson, hands down. Anyone that has to ask why needs to do some reading, if only
his Wikipedia page.