Here is the top five and a few other favorites. There is a pluses, minuses and summary for each GM.
1. R.C. Buford, San Antonio Spurs
2. Donnie Nelson, Dallas Mavericks
3. Joe Dumars, Detroit Pistons
4. Bryan Colangelo, Toronto Raptors
5. John Paxson, Chicago Bulls
Other notables…
10. Kevin O'Connor, Utah Jazz
19. Elgin Baylor, Los Angeles Clippers
23. Mitch Kupchak, Los Angeles Lakers
25. Isiah Thomas, New York Knicks
26. Billy King, Philadelphia 76ers
30. Kevin McHale, Minneosta Timberwolves
http://sportsillustrated.cnn.com/2007/writers/kelly_dwyer/06/25/gm.rankings/index.html