Lifetime WAR --
http://www.baseball-reference.com/le...t_career.shtml
Williams #11
Dimaggio #41
Single-season WAR --
http://www.baseball-reference.com/le...t_season.shtml
Williams top 3: #21, #25, #25 (tie)
Dimaggio top 3: #116, #226, #245
Since WAR includes both offensive and defensive statistics, it would seem that Williams, by a significant margin, was the superior player.