It looks like the ranking of fighters is this:
1. Jack (took out Sawyer, took out Ethan)
2. Sayid (not yet tested, but he was military and he tortured Sawyer)
3. Charlie ("you hit like a ponce")
4. Michael (beat up Jin, didn't knock him out or anything, but didn't lose either)
5. Sawyer (Lost to Dr Jack, showed ass against Charlie)
6. Jin (lost against Sawyer, Michael, and jobbed to Ethans rock)
7. Locke (great in a knife fight, looks to have jobbed against Ethan)
8. Boone (got beat up by Sawyer)
9. Hurley
10. Walt