Because I can, here's a run-down of my top 5:
1. Parvati - One of the best social, physical and strategic threats Survivor has ever seen. She's known for flirting, but she has been behind some of the best strategic plays ever: the Ozzy vote, she was part of the Erik blindside, and what many consider the best strategic move of all-time, two idols played for Jerri and Sandra. She constructed one of the strongest alliances ever, and one of the first successful females alliances - the Black Widow Brigade. Her social game is great, as she plays an aggressive, cutthroat game, but she manages to have strong enough relationships to get votes at the end. Her physical game is underrated, as she is phenomenal in endurance challenges - including beating Rupert when they needed to send him home.
2. Sandra - Two-time winner. Her first two games were "anyone but me", and that worked beautifully with the players she was working with. She knew nobody would vote for Russell in HvV, so she tolerated him all the way to the win. In Game Changers, she knew her "anyone but me" strategy would get her booted very early. So instead she took control of the game, and the only reason she was voted out was because of a lopsided tribe swap.
3. Rob - His work in All-Stars is brilliant, but his game was further along than Survivor had evolved at that point, costing him the game. He's cutthroat, but still manages to earn respect from fellow castaways. He's the best male ever when combining physical, social and strategic gameplay. No man has ever had a better combination than Rob. He sits at three because while his strategy was very effective in Redemption Island, his competition was not at a high level.
4. Kim - Kim challenges Parvati and Boston Rob as the best blend of social, physical and strategic gameplay. Like Rob, she controlled her season. She dominated challenges, she controlled every vote, and she is one of the most charming players to ever play the game. Her strategic gameplay was subtle, but she had everybody wanting to work with her and believing they could beat her. She sits at 4 only because we only have one season as a sample size, and some have knocked her for playing with lesser competition. Although she aligned with the better players in Sabrina and Chelsea, and took out the one person gunning for her - Troyzan - as soon as possible.
5. Tony - Tony was without a doubt the most reckless player to ever win. He was in many alliances and did unconventional things in order to further his game. Lying about the special idol's powers was one of the best strategic moves ever, as it really got him to the end. He had strong allies to lessen the blow when he blindsided weaker alliances he was in. He convinced Woo to take him to the end, even though Woo had no chance of beating him, and hands-down would have beaten Kass. His knack for finding idols was incredible. It's almost like he took Russell's playing style and tweaked it in order to make it work.