I will leave out religious as that would be my top three so I will say and this is assuming since I have the ability to time travel I'll be able to have a conversation with them

1 Ghengis Khan, always been fascinated with him, read so much about him despite so little being known

2 Tesla I'd explain to him that the government is withholding his secrets and convince him to give me the plans for some cheap energy so I could make a billion, I'll promise him I'll give some to charity.

3 one of the US founding fathers, either Madison or Washington, probably Madison. I'd go armed with documentation about police action, government action and supreme court decisions and I'd be very interested to hear his take on things. I would wait until the constitution is ratified as it wouldn't be fair to the guy to expect him to fix the ills of the US.