Huh, this is a very hard round...but mostly for different reasons that you might be thinking. 
4p - Nathan Drake. A sexy bad boy who steals treasure and gets some arse at the same time. What's not to love?
3p - Master Chief. Did you know that under his helmet, there's... another helmet?!
2p - Gordon Freeman. The silent nerd, who single-handely doomed the world only to save it later. Proof that science can take you far (i.e: pushing some carts around). He's hardly charismatic, though.
1p - Link. Just like Gordon Freeman, giving points to silent characters is always a hard thing to do. They're hardly charismatic (probably what makes the rest of the cast much more likeable, like Barney Calhoun in Half-Life 2 or Zelda in The Legend of Zelda), and most of them struggle to achieve what Chrono from Chrono Trigger was. I gave GF the edge over Link because Link is supposed to be different in each entry (minus sequels), plus making him even less likeable.