Best World Series winner: Very tough to pick, however, I'll pick the 1927 Yankees. HM: 98 Yankees (very close, I like their pitching staff better, but hard to go against the 27 Yankees lineup.), 76 Reds, 89 Athletics.
Best World Series loser: 1960 Yankees - they put up a 97-57 record in the regular season, winning the AL pennant by a comfortable 8 games. They followed this up by outscoring the Pirates 55-27 in their seven game series, only to lose in seven games. They followed this up with winning the World Series in the next two seasons. They also won the 1958 World Series, so a win here gives them four titles in five seasons. HM: 1906 Cubs (116-36 record, then won the next two World Series).