As a point of reference, here are the original "NBA 50", chosen in 1996:
Abdul-Jabbar, Archibald, Arizin, Barkley, Barry, Baylor, Bing, Bird, Chamberlain, Cousy, Cowens, Cunningham, DeBusschere, Drexler, Erving, Ewing, Frazier, Gervin, Greer, Havlicek, Hayes, Johnson, Jones (Sam), Jordan, Lucas, Malone (Karl), Malone (Moses), Maravich, McHale, Mikan, Monroe, Olajuwon, O'Neal, Parish, Pettit, Pippen, Reed, Robertson, Robinson, Russell, Schayes (Dolph), Sharman, Stockton, Thomas, Thurmond, Unseld, Walton, West, Wilkens, Worthy
In 2004, Elliot Kalb published a book called "Who's Better, Who's Best in Basketball?". While I can't endorse all of his selections, he attempted to 'revise' the top 50 list, to include a few more of today's players. It's a fun read, and he avoids the knee-jerk reaction of placing Jordan at the top of the list. This is how he ranked the top 50 players, in order:
O'Neal, Chamberlain, Jordan, Russell, Abdul-Jabbar, Bird, Johnson, Robertson, Duncan, Cousy, Pettit, West, Baylor, Malone (Moses), Erving, Olajuwon, Malone (Karl), Bryant, Mikan, Robinson, Barkley, Barry, Schayes, Havlicek, Thomas, Gervin, Stockton, Kidd, Pippen, Rodman, Frazier, Cowens, Iverson, McHale, Hayes, Payton, Walton, Ewing, Reed, Garnett, McGrady, Jones (Sam), Archibald, McAdoo, Cunningham, Monroe, Maravich, Miller, Wilkins, Drexler
His reason for placing Shaq # 1 (which I don't necessarily agree with) is that he claims that there has never been a time in NBA history during which the #1 player (Shaq) is THIS much better and more dominant that the #2 player (Tim Duncan).
For reference in comparing the lists, these players were original top 50, but were eliminated in Kalb's book:
Arizin
Bing
DeBusschere
Greer
Lucas,Jerry
Parish
Sharman
Thurmond
Unseld
Wilkens,Lenny
Worthy
These players were in Kalb's top 50, but not in the original 50:
Bryant
Duncan
Garnett
Iverson
Kidd
McAdoo
McGrady
Miller, Reggie
Payton
Rodman
Wilkins, Dominique
The following players are on both lists:
Abdul-Jabbar
Archibald
Barkley
Barry
Baylor
Bird
Chamberlain
Cousy
Cowens
Cunningham
Drexler
Erving
Ewing
Frazier
Gervin
Havlicek
Hayes
Johnson
Jones, Sam
Jordan
Malone, Karl
Malone, Moses
Maravich
McHale
Mikan
Monroe
O'Neal
Olajuwon
Pettit
Pippen
Reed
Robertson
Robinson, David
Russell
Schayes (Dolph)
Stockton
Thomas, Zeke
Walton
West
According to Kalb, there are 8 players who have some type of a legitimate argument to be called "the best player ever". They are:
1) Shaq
2) Wilt
3) Jordan
4) Russell
5) Abdul-Jabbar
6) Bird
7) Magic
8) Oscar
Tim Duncan is ranked 9th all time, but can not be included in this "best ever" group.
Even though no one will agree with all of his picks, it is a fun read. Lots of great trivia (Bill Russell was 10-0 in game sevens, etc)...