Everyone will have different criteria for this, but here's mine:
1. Individual contributions
2. Championship pedigree
3. Relative greatness in athlete's era
4. Attitude towards their craft
5. Performance in the clutch
Here's my opinion for Boston:
1. Bill Russell (Celtics)
2. Ted Williams (Red Sox)
3. Larry Bird (Celtics)
4. Bobby Orr (Bruins)
5. Tom Brady (Patriots)
6. Rocky Marciano (Boxer)
7. John Havlicek (Celtics)
8. David Ortiz (Red Sox)
9. Carl Yastrzemski (Red Sox)
10. Bob Cousy (Celtics)
11. Ray Bourque (Bruins)
12. John Hannah (Patriots)
13. Kevin McHale (Celtics)
14. Marvin Hagler (Boxer)
15. Pedro Martinez (Red Sox)
16. Robert Parish (Celtics)
17. Tedy Bruschi (Patriots)
18. Cam Neely (Bruins)
19. Tom Heinsohn (Celtics)
20. Roger Clemens (Red Sox)
1. Individual contributions
2. Championship pedigree
3. Relative greatness in athlete's era
4. Attitude towards their craft
5. Performance in the clutch
Here's my opinion for Boston:
1. Bill Russell (Celtics)
2. Ted Williams (Red Sox)
3. Larry Bird (Celtics)
4. Bobby Orr (Bruins)
5. Tom Brady (Patriots)
6. Rocky Marciano (Boxer)
7. John Havlicek (Celtics)
8. David Ortiz (Red Sox)
9. Carl Yastrzemski (Red Sox)
10. Bob Cousy (Celtics)
11. Ray Bourque (Bruins)
12. John Hannah (Patriots)
13. Kevin McHale (Celtics)
14. Marvin Hagler (Boxer)
15. Pedro Martinez (Red Sox)
16. Robert Parish (Celtics)
17. Tedy Bruschi (Patriots)
18. Cam Neely (Bruins)
19. Tom Heinsohn (Celtics)
20. Roger Clemens (Red Sox)