As I mentioned earlier, it's Willie Mays for me. He did everything well, no weaknesses in his game. He's at least in the top 200 of every statistical list if not the top 100, 50, 2o, 10, or 5.
The only other player in consideration for the title of "Greatest Baseball Player" is Babe Ruth in my opinion, he and Mays are clearly above everyone else. Ruth generally has a little bit better stats than Mays but Mays could do more things well and I think played in a tougher era to excel.
Barry Bonds is a great player but he's not in the top 200 in batting average, singles, and triples. How the heck can Babe Ruth have 59 more triples than Bonds (136 to 77). Mickey Mantle had three bad knees for 7 years and managed to run from home to third 72 times.
And I could never consider a player hitting in the .200s the greatest baseball player to ever live, gotta hit at least .300 to get mentioned in the same breath as those who do.